doc: massive refactor and simplification to migrate to mkdocs

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

doc/Makefile.am

@@ -1,4 +1,11 @@
+SUBDIRS = config
+
 docsdir   := @docdir@/doc
-docs_DATA  = config.md conditions.md distro.md plugins.md	\
-	     service.md signals.md svc-machine.png cmdline.md
+docs_DATA  = README.md build.md cmdline.md commands.md		\
+	     conditions.md distro.md example.md features.md	\
+	     index.md initctl.md keventd.md plugins.md		\
+	     requirements.md runlevels.md runparts.md		\
+	     service.md signals.md state-machine.md		\
+	     watchdog.md					\
+	     logo.png svc-machine.png svc-machine.svg
 EXTRA_DIST = $(docs_DATA)