Update logic for adjusting standby buckets for restored apps.

Instead of skipping over not yet installed apps, add them to a list and
update the PackageReceiver to handle freshly installed apps separately.
When an app is installed within the first 8 hours after a device is
restored, if the app is on the list, adjust its standby bucket to rare.

Bug: 214580000
Test: atest UsageStatsDatabaseTest
Test: manually verify buckets are restored
Change-Id: I79a0bb08fd383420aa72266e1d80c89e666bb981