Handle locale change and pacakge change in different way

- Stop using a custom callback from AM to detect locale changes
and use the LOCALE_CHANGED broadcast instead.

- This would open up a chance where a publisher app fetches
its won manifest shortcuts after a locale change but
ShortcutManager hasn't updated string resources.

- So instead, at every entry point from ShortcutManager, check
if the locale has changed, and if so, update all resources
(and reset throttling).

- Do the same for package change events too.  At every entry point
from ShortcutManager, check if the caller package has been updated,
or any target activities have been disabled.  If so, rescan the
caller package.

- We do *not* do the same check at the LauncherApps entry points,
because the launcher should use the callback to listen to
shortcut changes.

- Also stopped using PackageMonitor for now because we want to
set a higher priority and changing PackageMonitor at this point
seems too much for DR.

Bug 29895275
Bug 30123329

Change-Id: Ib4a2f626a936c7328e2cc032324f5c3d1c3b9122