Add simple mongoose/esp32 example (w/out mOS)

PUBLISHED_FROM=0e407a2fb328107540d753123fe027f43860d0ef

examples/ESP32_IDF/README.md

@@ -0,0 +1,18 @@
+This is a Mongoose "Hello, world" that can be compiled under Espressif IoT Development Framework for ESP32
+
+It connects to WiFi network and serves a "hello world" page.
+
+Most of the the boilerplate comes from [project_template](https://github.com/espressif/esp-idf-template) with minimal changes.
+
+For building the example, you need to have [Docker](https://www.docker.com/products/docker) and use our pre-built SDK container.
+To build just run in the example directory
+```
+$ make
+```
+
+Note: before building, change `WIFI_SSID` and `WIFI_PASS` macros in main/main.c file
+
+Once built, use [esptool](https://github.com/espressif/esptool) for flashing
+```
+$ python esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 115200 --before default_reset --after hard_reset write_flash -u --flash_mode dio --flash_freq 40m --flash_size detect 0x1000 build/bootloader/bootloader.bin 0x10000 build/esp32_idf.bin 0x8000 build/partitions_singleapp.bin
+```