VolumeZen: combine ringer/notification volume and zen.

- Implement a new volume panel widget, combining volume and
  zen mode + conditions.
- Show zen mode + conditions when modifying ringer or notification
  streams.
- Host the volume panel widget in a dialog when being controlled
  by the audio service / volume keys.
- Remove support for multiple sliders in the volume panel.
- Remove support for separate ringer + notification volumes
  in the volume panel.
- Move volume panel resources up to SystemUI.
- Create a new combined Notifications quick settings tile.
- Host the volume panel widget in the quick settings panel under
  Notifications.
- When the quick settings detail panel is visible, route the volume
  keys to the embedded widget instead of showing a redundant dialog.
- Create common styles for quick settings text to be closer to spec.
- Update the framework resources for the ringer stream.
- Show the ringer icons in global actions.
- Add "until you turn this off" back as a separate zen condition.
- Disable time condition buttons when they are N/A.
- Don't allow volume changes to set ringer mode silent.

Bug:15186070
Change-Id: Id5e321dd1d5e7c4cf3917027ffbdf7e80d38b00d