Set up base ScreenRecordingService infrastructure

This change adds:
 - the aidl interfaces to communicate between the user and
system processes;
 - notifications infrastructure to notifu the user about the ongoing
   screen recording;

Flag: EXEMPT BUGFIX
Bug: 368579013
Test: passes presubmits
Change-Id: I96b96f6c371fa009155e5a8be1f6dc153f7b7f5c