This makes the test faster and more robust in very a busy WiFi environment
(our CI) and still exercises the scenario of fragmenting the message on
both mqtt and ssl levels (binary size to send > mqtt buffer size)
esp_netif_init() returns standard esp_err_t error code (unlike tcpip_adapter init), so shall be checked for the return value
Also to make the initialization code more consistent.
Testing with predefined buffer sizes for MQTT as well as mbedTLS to
exercise fragmenting outgoing data on both layers. Example test compares
received partition with the actual binary file.
The MQTT broker URL used as default in the examples has ceased operation. All examples and documention have been updated to point to the new domain mqtt.eclipse.org.
This also required an update of the python example test scripts to use TLS 1.2
added docs and tests for mqtt library, small fixes (removed warnings, option for custom outbox, websocket bug fixed for longer transports). refactored to use common tcp_transport component, support for CMake build system.
Closes#2108
