[Bluetooth] Implement health profile API and improve extension

- add Bluetooth Health Profile related API
- use BluetoothInstance::Initialize method
- call missing ondevicedisappeared callback
- improve server and client socket part
- fix many error code returns
- fix some readonly attributes to pass some TCT tests

BUG related to XWALK-1065
I think `_addConstProperty(this, 'isConnected', (msg.connected == 'true'));` is enough.