HDR: MDCV and CLL should not be exposed as a caps
In the case of HDR10+ dynamic meta (see #700 (moved)), the GOPs or scene can change MDCV and CLL values during the stream playback.
A GstVideoMeta approach should be considered instead of caps.
Only the type of HDR (HDR10, HDR10+, DolbyVision) should be exposed by caps allowing downstream element to adapt and optimize data retrieval.