Service notification overhaul

Updated session service notification.
Now changes color and text when the connection closes due to a
session timeout.
Added "Open" and "Exit" quick actions to notification.
Text is now localized to string XML file.
Fixed a concurrency issue where the AppRTC activity would exit
before fully unbinding from the service, causing it to stay
subscribed to state change notifications.
Fixed a couple of concurrency issues that caused auth prompts not
to correctly be displayed after an auth failure or session timeout.
Consolidated cases and toasts where the AppRTC activity exits and
creates an authentication prompt.