Adding APIs to get manifest entries for Launcher activities and widgets

and getting resources for a particular config

This would allow fetching display infos for the activity in a particular
config independent of system config.

Bug: 156154533
Test: Included CTS
Change-Id: Ie245d685fb21444c10a88b4ca86dc7ff08e2b599
Merged-In: Ie245d685fb21444c10a88b4ca86dc7ff08e2b599