Secure screenshot and screenrecord

* Partial port-forward of Screenshot toggle
* Creates an android:permission for both screenshot and screenrecord,
  as well as corresponding Intents. This disallows rogue apps to access these
  methods in PhoneWindowManager ( takeScreenshot() and takeScreenrecord() ) and
  hijack our system, by locking them down to System and SystemUI with said permissions.

* This is required for the Screenshot toggle, and reimplementation of screenshot navbar action

Change-Id: I4adac71a0ce924de96c9a7d495b42ae68441e4ad
Signed-off-by: Brandon McAnsh <brandon.mcansh@gmail.com>