Introduce the RUN_BACKUP_JOBS permission.

This is a new app-op permission which will be reserved for apps whose
primary purpose is to backup or sync content. Holding this permission
will allow the app to run longer backup-related jobs.

This permission will be denied by default and users will have to
navigate to the relevant Special App Access page in Settings to grant an
app the permission.

Bug: 318731461
Test: atest AppOpsTest
Change-Id: I2b1257fa557b5b7fb0acf6046f912611a99f7d14