Fork a new developer options page.

- Create a new activity/fragment and add it to manifest
- Mark old activity/fragment deprecated
- Enable/disable the new activity based on FeatureFlag
- Initial skeleton code for new fragment

Bug: 65522852
Test: make RunSettingsRoboTests -j40 ROBOTEST_FILTER=DevelopmentSettingsDashboardFragmentTest
Change-Id: Ib1395693f8b6f61d4726573a9ea841ea53cf207b