Create tutorials for V2 features

[microbit-mark]

Once the latest micro:bit reaches general availability, we will need new tutorials for the latest features in https://microbit-micropython.readthedocs.io

TODO

Draft new pages for:

• Ways to identify if you're on a V2
• Speaker
• Microphone
• Sound Emoji
• Logo
• Touch Modes Add set and get touch modes for touch pins #14