Revert "Custom lockscreen"

The UI of the feature does not fit android guidelines and the feature itself seems a bit too much for me.

This reverts commit 2fa74b852a8e5750adbb5fa2f8db2b935ce56f06.

Change-Id: I3641ffba528b128015dbc1917938d472807a10db
Merge "Revert "Custom lockscreen"" into kitkat