Create a new region picker page

1. The region which is selected in region picker will also apply to the first locale.
2. When a user change the first locale, the region of the first locale will be updated to the region picker.

Bug: 385047778
Flag: com.android.settings.flags.regional_preferences_api_enabled
Test: check hsv
Change-Id: I001e0910ce9d1601513ed2f52e6ee30d3551859f