Add getServices to BLE

[evhan55]

Resolves

104: BLE 'getServices' possibly not implemented

Proposed Changes

• Add 'getServices' handler to both macOS and Windows BLESession

Notes

• This PR used to live here: https://github.com/LLK/scratch-link/pull/115, before the LLK/scratch-link repo changed permissions. There is some discussion regarding the code and changes there.

[evhan55]

@cwillisf This code is ready for a fresh review anytime. Thanks for the comments back in PR #115.

Here are log results from pressing the new Get services of connected peripheral button after connecting to a micro:bit in playground.html:

• macOS:

  Received message: {"result":["0000180A-0000-1000-8000-00805f9b34fb","0000F005-0000-1000-8000-00805f9b34fb"],"jsonrpc":"2.0","id":3}
  getServices resolved to: ["0000180A-0000-1000-8000-00805f9b34fb","0000F005-0000-1000-8000-00805f9b34fb"]

• Windows:

  Received message: {"jsonrpc":"2.0","id":2,"result":["00001800-0000-1000-8000-00805f9b34fb","00001801-0000-1000-8000-00805f9b34fb","0000180a-0000-1000-8000-00805f9b34fb","0000f005-0000-1000-8000-00805f9b34fb"]}
  getServices resolved to: ["00001800-0000-1000-8000-00805f9b34fb","00001801-0000-1000-8000-00805f9b34fb","0000180a-0000-1000-8000-00805f9b34fb","0000f005-0000-1000-8000-00805f9b34fb"]

[evhan55]

Ok thanks! I will merge this here and then open an issue to improve with bit manipulation