GD metrics: Logging link layer events from GD

Events include:
* LinkLayerConnection,
* ReadRssi,
* ReadFailedContactCounter,
* ReadTxPower,
* RemoteVersionInfo,
* HciTimeout
Also move the gd metrics logging from common to os

Test: gd/cert/run
Manual test: build and run Bluetooth (connection, pairing, music and phone
call)
Bug: 181819141
Tag: #gd-refactor
BYPASS_LONG_LINES_REASON: Bluetooth likes 120 lines

Change-Id: Id84651a4cc0343ed0438083290b3aaab1ead6535