[ENHANCEMENT] Show a snackbar when the session expires

[michaeltroger]

Is your feature request related to a problem? Please describe.
When fingerprint authentication is enabled then there is no information when the session runs out, other than being redirected to the locked screen.

Describe the solution you'd like
It would be great to show an info text (snackbar at the bottom) for a couple of seconds after the session expired.

Describe alternatives you've considered
x

Additional context
Look at the George app for an example