Floss: Implement Pandora GATT profile (part1).

Bug: 300954028, Bug: 300954029, Bug: 300954030, Bug: 300954031, Bug: 300942864, Bug: 300942865
Test: mma packages/modules/Bluetooth && pts-bot GATT
Tag: #floss
Flag: EXEMPT floss only changes
Change-Id: I4f4a75f39cde754f66f005169f3041dc7f297040