Support for BLE and BTP

[ivmarkov]

Currently runs on Linux/BlueZ only, but adding support for another BLE stack should be easy (user needs to implement the GattPeripheral trait - and - we might add out of the box BLE/GATT box implementations to rs-matter over time, as we did for mDNS).

Keeping as Draft for now, as the code needs to be tested on MCUs (doing this just now with ESP-IDF + Bluedroid) and needs unit tests.