Settings: Remove lockscreen options from security.

  - Create a separate fragment for Lockscreen settings
  - Move App Security up in Security Settings
  - General clean up

Change-Id: I4dc20942b87c2446c7e798e28f7e475efebaddb8
Settings: Fix missing preference when lockscreen disabled.

    - Introduced in security settings reshuffle.

Change-Id: I1b6b608682208396d5efc54fd985652f65e86ffc
security settings cleanups, move wakelock blocker to top, update gradle

Change-Id: Id4b0fd426f73345b3eea594652236b47ba5a8be3