Tracked keyboard

Implements:

• A device manager that monitor VR devices connections and alert the operator if something required is missing;
• A tracked keypad for the participant with a control over the estimations generic inputs, 3D animated model, and a modal to control the pairing with the real keyboard.

Bonus: Starts the cleanup with the new naming convention (respecting the lower case for the first word of any kind of property of a class) and add better failsafes for the serialized fields.