Heads up: Add blacklist feature (1/2)

Credits to AOSPA Team

Change-Id: I976587d779319116a65f2f0851481b3db6d11821
Heads up: User configurable timeout (1/2)

Change-Id: I263f8ea013f99488c2d1af97eff517db2b9d634b
Heads up: option to launch in floating window (1/2)

This commit also affects Hover

Change-Id: Ia8ffb4088f5b48b222a77ef486ba8b14e193c26f
HeadsUp: Filter out notifications from system uid packages.

    - Settings is very spammy in its notifications, so lets
    just ignore them.

Change-Id: Ic269e8727efb2021d76cccecb9f7e555034d1925