Replaces DesktopModeStatus with two objects.

Replaces a set of static methods with two objects:

1) DesktopModeConfig, which should only be used within WM Shell and
   contains constants needed for Desktop Experiences.
2) DesktopModeFeatures, which will be shared between WM Shell, System UI
   and Launcher, containing properties and methods to check what is
   enabled or not within Desktop Experiences.

Bug: 395863348
Test: atest DesktopModeConfigImplTest
Test: atest DesktopModeFeaturesImplTest
Flag: EXEMPT (refactoring)
Change-Id: I5c7d2903169a42579284344f5d87a36669f14410