frameworks: Lockscreen Notifications (1/2)

My try on making notifications easily accessable from lockscreen.
Credits to ChameleonOS, I got the notification listener permission and
some small other stuff from their ActiveDisplay implementation.

Lockscreen Notifications allow you to manage all your notifications
directly on the lockscreen.

Features:
- Pocket mode turn screen on when phone is pulled out of pocket and
turn it off when phone gets back in pocket
- Hide low priority notifications
- Hide non-clearable notifications
- Allow dismissing even non-clearable notifications from lockscreen
- Just turn screen on when there's currently a notification pending
- Toggle between expanded and normal notification view by longpressing

This should still be considered as beta, even if it seems to work very
well for me.

Bug fixes: build fix