floss: metrics: A2DP Sink profile connection state handling

Route the A2DP Sink profile connection events route to the metrics
processing unit. Then, parse the event into structured metrics
compatible format.

BUG: 240781725
Tag: #floss
Test: emerge-${BOARD} floss
BYPASS_LONG_LINES_REASON: Bluetooth likes 120 lines

Change-Id: I685d9c2962b62aa9cb1a70cd12900f93a81b4424