[Library Manager] Please add library painlessMesh

[BlackEdder]

https://gitlab.com/painlessMesh/painlessMesh

This library enables mesh functionality for both esp32 and esp8266 boards.

[BlackEdder]

Note that in the next version we'll most likely add ESPAsyncTCP and AsyncTCP to our dependencies, which I don't think are in the library manager yet?

[cmaglie]

Done. No ESPAsyncTCP nor AsyncTCP has been added in the library manager yet.