Make AmbientState injectable

1) Mark AmbientState as SysuiSingleton to allow access from
- PanelBar
- NotificationStackScrollLayout

2) Mark AmbientState constructor with @Inject
   for Dagger use when needed

3) Ensure that AmbientState params are injectable
- Context --- AmbientState is now global, and has access to application
  context; we can leave this unchanged (otherwise we mark it with
  @Named(VIEW_CONTEXT) to ask for the subcomponent view context)
- SectionProvider --- bind to NotificationSectionsManager in
  NotificationsModule, the closest module to AmbientState

4) Add AmbientState to constructors for NSSL and NPVC
- Have PanelBar update AmbientState directly (via PVC) instead of
  piping changes through layers of classes

Fixes: 177921542
Test: log to verify that shade open state updates correctly
Test: build sysui-studio with
       sysuiTestDebug variant and SystemUITests config, then run:

adb shell am instrument -w -e class com.android.systemui.statusbar.notification.stack.NotificationStackScrollLayoutTest com.android.systemui.tests

Change-Id: I0a50d603b49c9f55f1af41084974aee59e9ce95b