Whitelist for package broadcasts

This change adds a whitelist of UIDs that package change broadcasts may
be sent to. This must be pre-calculated and stored in memory before the
package is updated or modified as the visibility may change during that
transaction.

Test: atest PackageManagerTests AppsFilterTest AppEnumerationTests
Fixes: 143534210
Change-Id: I003c54528141d8b03033f8241559dd5895df064a