The MR adds implementations (+ a few tests) for the following methods in `bluetoothapis.h`:
* `BluetoothSdpEnumAttributes` * `BluetoothSdpGetContainerElementData` * `BluetoothSdpGetElementData` * `BluetoothSdpGetAttributeValue`
-- v23: bluetoothapis: Implement BluetoothSdpGetAttributeValue. bluetoothapis/tests: Add tests for BluetoothSdpGetAttributeValue. bluetoothapis: Add stub for BluetoothSdpGetAttributeValue. bluetoothapis: Implement BluetoothSdpEnumAttributes. bluetoothapis/tests: Add tests for BluetoothSdpEnumAttributes.