usability improvements

[TobiasRoeddiger]

• [x] BLE characteristic für button press: BLE notify if button was pressed, notify again if it was pressed again, etc.
• [x] section 1: general setup, section 2: BLE API Usage, section 3: low level functions
• [x] audio player: send wav file name via BLE, if emptry string stop audio, remove integer logic for playing files
• [x] ignore mic collision
• [x] clearly document the BLE API, even though it is edge-ml, it should be in our docs too
• [x] remove the last column in the config table
• [x] #15

[Xraydylan]

I found a cleaver way to leave freq tone still in.

For the simple usage it can be disregarded. But if any more complex stuff is needed, it can be used.

I will not mention the freq tone in the BLE API Usage section and only mention in together with the low level functions and further functionality.

[TobiasRoeddiger]

OpenEarable_open-earable at v4_experimental_mess_comments.pdf