Apply display override config for secondary displays

Now display-specific settings, such as dimensions and orientation,
are stored in display override config. For default display it is
mirroring the global config. Each time when global config is updated,
override of the default display should be updated too and vice versa.

Test: Existing and manual tests still pass.
Change-Id: Ic6c2190092d328820f314a05bed43c875db18170