Should fix keepassxreboot#7695: TouchID and Apple Watch support is now detected both at compile time and runtime

Each authentication method can become unavailable during runtime:
user can close the laptop lid or take off the watch.

This also means that we probably have to add some sort of timer to the
DatabaseOpenWidget to check the unlock method periodically in case
if quick unlock is enabled and a previously unavailable authentication
method becomes available again.

- Password data removal
- TODOs and descriptions for some functions