Load suggestions through SettingsIntelligence.

- Add flag to switch between old/new implementation
- Add SuggestionLoader to load using Loader (instead of AsyncTask)
- Update DashboardAdapater/SuggestionAdapter to take List<Suggestion>
- Marked old getter/setters as @Deprecated and added comment
- Update tests to cover suggestionV2 adapter changes.

TODO:
- Handler for dismissing suggestion not set up yet.
- Suggestion data structure is incomplete (missing icon, remote view, etc)
- Need to extend Suggestion data strcture to support icon and
  remote view binding

Bug: 65065268
Test: robotests
Change-Id: I2378ef4c9edee972d5de93c3868068e2cde23f56