MQTT - HA integration update & PlatformIO environment

[aly-fly]

• Added PlatformIO environment for ESP32 (-S3 has to be added & tested)
• Added hard-reset of the WiFi hardware before first connection (helps more reliable connection startup)
• Added publishing of the online message (on startup) and offline message (LWT) which is read by the HA integration, which sets Media Player to state unavailable
• Added playlist example file (stations should be checked if still alive)

[trip5]

Hey aly-fly. Like your changes.

You should move your .gitignore list into .git/info/exclude so it doesn't appear in the files here. It follows the same format.

[e2002]

Hi! Request is partially included in v0.9.550. Thanks for your help!
https://github.com/e2002/yoradio/blob/main/yoRadio/src/core/network.cpp#L74