BluetoothMetrics: Add counter metrics in GD cpp

1) Provide API CounterMetrics.Count() to other
bt components
2) Cache the counters
3) Send the counters to westworld every 6 hours and
before Bluetooth is closed

Bug: 204823249
Tag: #feature
Test: atest bluetooth_test_gd_unit
Change-Id: I9cd6ac9e79bfe5d378c13caa3fd2a76a27c1e025