PackageManager: make protected-broadcasts permission aware

This extends the <protected-broadcast> mechanism to allow protecting
actions based on a permission for system apps.

For instance:

   <protected-broadcast android:name="ACTION_A"
                        android:permission="PERMISSION_X" />

will restrict intents with action "ACTION_A" to be only sent with
apps holding the "PERMISSION_X" permission. Note that system UIDs will
bypass the permission check and always be allowed, just like the normal
protected-broadcast mechanism.

You must still be a system application to delcare a protected broadcast.

Change-Id: Id25cffd233d400800dcb5249c5f487134e1b4152
Signed-off-by: Roman Birg <roman@cyngn.com>