Merge changes from topics "footer-actions-fakes", "footer-actions-mad",...

Merge changes from topics "footer-actions-fakes", "footer-actions-mad", "footer-actions-screenshots" into tm-qpr-dev

* changes:
  Enable the new footer actions in team food.
  Add screenshot test for the footer actions (2/2)
  Implement LaunchableView for footer actions Views.
  Wire the new FooterActions implementation behind a flag
  Implementation of the FooterActions following the MAD (1/3)
  Add BroadcastDispatcher.broadcastFlow
  Extract QSSecurityFooterUtils out of QSSecurityFooter
  Make the logic of QSSecurityFooter reusable
  Add some fakes to SystemUI-test-utils
  Allow preventing unrestricted Apps from being Stopped