Remove old docs, rename docs_new to docs

It would be probably good idea to also remove tools/docgen.py and
asciidoc.mk, but asciidoc.mk is still mentioned under `cloud/doc`, which
may contain some useful info which we'll need at least to review before
removing.

PUBLISHED_FROM=faf454d4c52a2f07ea8ac084cf0bd11a0c9c9b3b

docs/c-api/mqtt.h/intro.md

@@ -0,0 +1,8 @@
+---
+title: "MQTT"
+symbol_kind: "intro"
+decl_name: "mqtt.h"
+---
+
+
+

docs/c-api/mqtt.h/items.json

@@ -0,0 +1,80 @@
+{
+    "items": [
+        {
+            "type": "markdown",
+            "name": "intro.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_set_protocol_mqtt.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_send_mqtt_handshake.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_send_mqtt_handshake_opt.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_publish.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_subscribe.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_unsubscribe.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_disconnect.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_connack.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_puback.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_pubrec.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_pubrel.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_pubcomp.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_suback.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_unsuback.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_ping.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_pong.md"
+        },
+        {
+            "type": "markdown",
+            "name": "mg_mqtt_next_subscribe_topic.md"
+        },
+        {
+            "type": "markdown",
+            "name": "struct_mg_mqtt_topic_expression.md"
+        }
+    ]
+}

docs/c-api/mqtt.h/mg_mqtt_connack.md

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+---
+title: "mg_mqtt_connack()"
+decl_name: "mg_mqtt_connack"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_connack(struct mg_connection *nc, uint8_t return_code);
+---
+
+Send a CONNACK command with a given `return_code`. 
+

docs/c-api/mqtt.h/mg_mqtt_disconnect.md

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+---
+title: "mg_mqtt_disconnect()"
+decl_name: "mg_mqtt_disconnect"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_disconnect(struct mg_connection *nc);
+---
+
+Send a DISCONNECT command. 
+

docs/c-api/mqtt.h/mg_mqtt_next_subscribe_topic.md

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+---
+title: "mg_mqtt_next_subscribe_topic()"
+decl_name: "mg_mqtt_next_subscribe_topic"
+symbol_kind: "func"
+signature: |
+  int mg_mqtt_next_subscribe_topic(struct mg_mqtt_message *msg,
+                                   struct mg_str *topic, uint8_t *qos, int pos);
+---
+
+Extract the next topic expression from a SUBSCRIBE command payload.
+
+Topic expression name will point to a string in the payload buffer.
+Return the pos of the next topic expression or -1 when the list
+of topics is exhausted. 
+

docs/c-api/mqtt.h/mg_mqtt_ping.md

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+---
+title: "mg_mqtt_ping()"
+decl_name: "mg_mqtt_ping"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_ping(struct mg_connection *nc);
+---
+
+Send a PINGREQ command. 
+

docs/c-api/mqtt.h/mg_mqtt_pong.md

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+---
+title: "mg_mqtt_pong()"
+decl_name: "mg_mqtt_pong"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_pong(struct mg_connection *nc);
+---
+
+Send a PINGRESP command. 
+

docs/c-api/mqtt.h/mg_mqtt_puback.md

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+---
+title: "mg_mqtt_puback()"
+decl_name: "mg_mqtt_puback"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_puback(struct mg_connection *nc, uint16_t message_id);
+---
+
+Send a PUBACK command with a given `message_id`. 
+

docs/c-api/mqtt.h/mg_mqtt_pubcomp.md

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+---
+title: "mg_mqtt_pubcomp()"
+decl_name: "mg_mqtt_pubcomp"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_pubcomp(struct mg_connection *nc, uint16_t message_id);
+---
+
+Send a PUBCOMP command with a given `message_id`. 
+

docs/c-api/mqtt.h/mg_mqtt_publish.md

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+---
+title: "mg_mqtt_publish()"
+decl_name: "mg_mqtt_publish"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_publish(struct mg_connection *nc, const char *topic,
+                       uint16_t message_id, int flags, const void *data,
+                       size_t len);
+---
+
+Publish a message to a given topic. 
+

docs/c-api/mqtt.h/mg_mqtt_pubrec.md

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+---
+title: "mg_mqtt_pubrec()"
+decl_name: "mg_mqtt_pubrec"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_pubrec(struct mg_connection *nc, uint16_t message_id);
+---
+
+Send a PUBREC command with a given `message_id`. 
+

docs/c-api/mqtt.h/mg_mqtt_pubrel.md

@@ -0,0 +1,10 @@
+---
+title: "mg_mqtt_pubrel()"
+decl_name: "mg_mqtt_pubrel"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_pubrel(struct mg_connection *nc, uint16_t message_id);
+---
+
+Send a PUBREL command with a given `message_id`. 
+

docs/c-api/mqtt.h/mg_mqtt_suback.md

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+---
+title: "mg_mqtt_suback()"
+decl_name: "mg_mqtt_suback"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_suback(struct mg_connection *nc, uint8_t *qoss, size_t qoss_len,
+                      uint16_t message_id);
+---
+
+Send a SUBACK command with a given `message_id`
+and a sequence of granted QoSs. 
+

docs/c-api/mqtt.h/mg_mqtt_subscribe.md

@@ -0,0 +1,12 @@
+---
+title: "mg_mqtt_subscribe()"
+decl_name: "mg_mqtt_subscribe"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_subscribe(struct mg_connection *nc,
+                         const struct mg_mqtt_topic_expression *topics,
+                         size_t topics_len, uint16_t message_id);
+---
+
+Subscribe to a bunch of topics. 
+

docs/c-api/mqtt.h/mg_mqtt_unsuback.md

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+---
+title: "mg_mqtt_unsuback()"
+decl_name: "mg_mqtt_unsuback"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_unsuback(struct mg_connection *nc, uint16_t message_id);
+---
+
+Send a UNSUBACK command with a given `message_id`. 
+

docs/c-api/mqtt.h/mg_mqtt_unsubscribe.md

@@ -0,0 +1,11 @@
+---
+title: "mg_mqtt_unsubscribe()"
+decl_name: "mg_mqtt_unsubscribe"
+symbol_kind: "func"
+signature: |
+  void mg_mqtt_unsubscribe(struct mg_connection *nc, char **topics,
+                           size_t topics_len, uint16_t message_id);
+---
+
+Unsubscribe from a bunch of topics. 
+

docs/c-api/mqtt.h/mg_send_mqtt_handshake.md

@@ -0,0 +1,10 @@
+---
+title: "mg_send_mqtt_handshake()"
+decl_name: "mg_send_mqtt_handshake"
+symbol_kind: "func"
+signature: |
+  void mg_send_mqtt_handshake(struct mg_connection *nc, const char *client_id);
+---
+
+Send MQTT handshake. 
+

docs/c-api/mqtt.h/mg_send_mqtt_handshake_opt.md

@@ -0,0 +1,11 @@
+---
+title: "mg_send_mqtt_handshake_opt()"
+decl_name: "mg_send_mqtt_handshake_opt"
+symbol_kind: "func"
+signature: |
+  void mg_send_mqtt_handshake_opt(struct mg_connection *nc, const char *client_id,
+                                  struct mg_send_mqtt_handshake_opts);
+---
+
+Send MQTT handshake with optional parameters. 
+

docs/c-api/mqtt.h/mg_set_protocol_mqtt.md

@@ -0,0 +1,20 @@
+---
+title: "mg_set_protocol_mqtt()"
+decl_name: "mg_set_protocol_mqtt"
+symbol_kind: "func"
+signature: |
+  void mg_set_protocol_mqtt(struct mg_connection *nc);
+---
+
+Attach built-in MQTT event handler to the given connection.
+
+The user-defined event handler will receive following extra events:
+
+- MG_EV_MQTT_CONNACK
+- MG_EV_MQTT_PUBLISH
+- MG_EV_MQTT_PUBACK
+- MG_EV_MQTT_PUBREC
+- MG_EV_MQTT_PUBREL
+- MG_EV_MQTT_PUBCOMP
+- MG_EV_MQTT_SUBACK 
+

docs/c-api/mqtt.h/struct_mg_mqtt_topic_expression.md

@@ -0,0 +1,13 @@
+---
+title: "struct mg_mqtt_topic_expression"
+decl_name: "struct mg_mqtt_topic_expression"
+symbol_kind: "struct"
+signature: |
+  struct mg_mqtt_topic_expression {
+    const char *topic;
+    uint8_t qos;
+  };
+---
+
+puback 
+