Reveal color standard, transfer, and range.

We've already been parsing them for many years, and they're well
defined by other public APIs, so let's reveal them in MediaStore.

Also get some storage-related documentation updated to guide
developers towards replacements in a post-scoped-storage world.

Bug: 140247264, 139185855, 141523097, 139185322
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: Id39a74a9972a330b3f83913b2eef5100ec59627d