Move the app list in battery settings to PreferenceController. So that
we can:
1. Clean the code in PowerUsageSummary
2. Make it easy to add/move the app list to other place in furture.
This cl:
1. Move and make it invisible since in P we don't show app list in
battery main page.
2. Move related test to BatteryAppListPreferenceControllerTest
Bug: 70234293
Test: RunSettingsRoboTests
Change-Id: Ice7a42394916ff5e71305bfe22f5c35868d87fc7
1240549591