Camera: Add a new tag for multi-resolution stream support

- The new tag is used to remove the ambiguity when a physical camera is
backing more than one logical cameras.
- Add missing VTS tests for multi-resolution stream.

Test: Camera CTS, VTS
Bug: 156254356
Bug: 184663916
Change-Id: I8adc152bbf57e8ec5e058834c1c6f461aca1bcbd