ESP32 listener update

[tuomastiihonen]

After (perhaps a bit hastily, it transpires) customising the generic ESP32 listener code to the C3 variant, I embarked on figuring out mdns provisioning. That's now done — the listener prioritises a saved TA server but queries mdns if it finds none. If multiple servers are found, the client picks the first one it finds. If no server is configured or found via mdns, the listener restarts itself to avoid hanging on trying to connect to nothing.

I've also added an option to run two Neopixel strips with an intention to add eg. only showing flashing on one of the strips.

Other updates:

• If disconnected, websocket waits for 2s between reconnect attempts (was a bit floody)
• Extra LEDs work now (current version wasn't stripping quotes from activeType)
• Configured strips turn blue for 1s on boot and then shut (I'll make them flash in some other colour when the server connection is established)
• Flashing is now in yellow and the strip returns to activeType after flashing

I'm going to do a pr later today or tomorrow, removing the C3 variant and updating the generic listener.

Ideas for further development?

[josephdadams]

Be sure to update the docs and include pics if you want