We are running out of int flags for public API methods such as
PackageManager.getPackageInfo(String packageName, int flags). As a
solution, we will change the flags param to Flags objects. At the
same time, we deprecate the old methods that directly use int flags.

The new flags classes are: ApplicationInfoFlags, PackageInfoFlags,
ComponentInfoFlags and ResolveInfoFlags. Because there are already
annotations of the same names, we renamed the annotations to *FlagsBits.

Old API usage example:
getPackageInfo(pkgName, MATCH_UNINSTALLED_PACKAGES)

New API usage example:
getPackageInfo(pkgName, PackageInfoFlags.of(MATCH_UNINSTALLED_PACKAGES))

See b/204433742 for discussions.

CTS-Coverage-Bug: 206147270
BUG: 204432643
BUG: 204433659
Test: manual
Change-Id: I8ab2adad6907670c5879c043d170c950afefe46c