Separte device specific implementations per device generation type

[Thaodan]

Similar as done in Gadget bridge features such as notifications should be separated where possible.
For example right now the notification logic is specific to the first generation gadget bridge.

I saw some effort doing this already however I'm not sure if there was a generic bug for this topic.

[piggz]

This sort-of exists already using the class hierarchy and overriding of methods. Later devices have certain features overridden.
The current hierarchy is basically GTR2 > GTS2 > GTS > Bip

Happy to accepts code-cleanups :)