Move rounded corner to provider

Move rounded corners code from ScreenDecorations.
1. Move business logic to RoundedCornerDecorProviderFactory.
2. Move view and inflating into RounedCornerDecorProviderImpl.

Bug: 218951516

Test: atest ScreenDecorationsTest \
            OverlayWindowTest \
            PrivacyDotDecorProviderFactoryTest \
            RoundedCornerDecorProviderFactoryTest \
            RoundedCornerResDelegateTest
Test: Manually testing rounded corner when display size, rotation
      changed on normal devices, foldable devices, and hardware-overlay
      devices

Change-Id: I60e8a0ceaca19dc45117fb98db45f4063cbfe1b3