custom BLE service for controlling the LED

Create a custom BLE service for controlling the LED from previous semester. Basic functions:

Custom service that is discoverable via BLE
BLE characteristic that could be used to change the LED color
BLE characteristic that could be used to read the LED color and can notify the user that the color has changed
Persistent storage: color should persist the board restart
Optional: BLE security - secure the color change characteristic so that it can be used only after pairing.

Vafo / ESTC-project