Implement extra persistence layer for widget provider info

Currently widget provider info are loaded from the manifests of
respective packages, which is not performant since loading the
resources from various apps could take a while.

This CL does the following:
1. Instead of persisting only the providers that are bound to the
   workspace, we persists all providers.
2. In addition to providers, we also persists the provider info to avoid
   loading them from app's resource during a reboot.

Bug: 202356231
Test: atest AppWidgetServiceImplTest
Change-Id: I91fead0b61b0cb84d876dd05781a585805a01400