Volume: Simple dialog footer, DND in quick settings.

 - Show DND tile by default, this is now the only
   place to manage DND modes / end conditions.
 - Remove super footer from volume dialog, replace with
   a simplified version that displays the current mode
   and allows ending DND.
 - Remove obsolete text-only footer from codebase.
 - Migrate remaining volume items into main resource files.
 - Rename "No interruptions" to "Total silence".
 - Add new user information banner for "Total silence"
 - Crude media filtering for Total Silence.
   (deeper muting changes will be done as a followup)
 - Disable volume dialog sliders completely if muted due
   to zen.
 - Cleanup ZenModePanel: assume embedded mode, remove
   expandable subhead
 - Remember "favorite" DND mode inside the DND config panel.
 - AudioService: consult ringer-mode-delegate before voluming
   down into silent.
 - Add new hour options to time-based exit conditions.
 - Volume dialog visual updates to move closer to final visuals.
 - Unify ringer=silent with DND.

Bug: 19260237
Change-Id: I05d7e001eca3b5125418ec3bc4087d0cb8866717