Tracking issue for BLE support

[lukipuki]

Is your feature request related to a problem? Connecting to a device via BLE is not supported.

Describe the solution you’d like Use the btleplug crate for easy cross-platform BLE support. The interface should be almost the same as for serial and TCP connection.

Additional context This is more complex than serial/TCP support, as the BLE API is a bit complex.

• [x] implement build_ble_stream
• [ ] add example
• [ ] update docs
• [ ] add a function to discover Meshtastic devices