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
- Wake on new notification
- Configure notification count displayed at once
- Privacy Mode: disable showing notification content.
- Blacklist apps - thanks to ChameleonOS for the original implementation and @Der-Schubi for bringing it to lockscreen notifications

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

Change-Id: I4d72de71d36dc2f66ad7e3ce7a4442a931cf2982