le_broadcast: Initial alignment of service with the API

This aligns the .aidl interfaces, adds the callback
registration mechanism, exposes profile in the
Bluetooth Adapter and stitches together basic API
calls with the service implementation.
It does not bring the BluetoothLeBroadcastMetadata
support yet.

Bug: 150670922
Bug: 210985995
Tag: #feature
Test: atest BluetoothInstrumentationTests
Sponsor: jpawlowski@

Change-Id: Ia454badc4f95a4b9953e57709a680f178ebfea45