docs(common): improving documentation

- update esp_modem to use esp_docs
- migrated docs from github pages to docs.espressif.com

docs/asio/en/index.rst

@@ -0,0 +1,42 @@
+ASIO port
+=========
+
+Overview
+--------
+Asio is a cross-platform C++ library, see https://think-async.com/Asio/. It provides a consistent asynchronous model using a modern C++ approach.
+
+
+ASIO documentation
+^^^^^^^^^^^^^^^^^^
+Please refer to the original asio documentation at https://think-async.com/Asio/Documentation.
+Asio also comes with a number of examples which could be find under Documentation/Examples on that web site.
+
+Supported features
+^^^^^^^^^^^^^^^^^^
+ESP platform port currently supports only network asynchronous socket operations; does not support serial port.
+SSL/TLS support is disabled by default and could be enabled in component configuration menu by choosing TLS library from
+
+- mbedTLS with OpenSSL translation layer (default option)
+- wolfSSL
+
+SSL support is very basic at this stage and it does include following features:
+
+- Verification callbacks
+- DH property files
+- Certificates/private keys file APIs
+
+Internal asio settings for ESP include
+
+- EXCEPTIONS are enabled in ASIO if enabled in menuconfig
+- TYPEID is enabled in ASIO if enabled in menuconfig
+
+Application Example
+-------------------
+ESP examples are based on standard asio :example:`examples <../examples>`:
+
+- :example:`udp_echo_server <../examples/udp_echo_server>`
+- :example:`tcp_echo_server <../examples/tcp_echo_server>`
+- :example:`asio_chat <../examples/asio_chat>`
+- :example:`ssl_client_server <../examples/ssl_client_server>`
+
+Please refer to the specific example README.md for details