Add compound clip functionality

As mich as I love Resolve, I really would love to see more implementations and functions coming regarding compound clips / subclips (as they are called in Avid).
Ideas to improve:

1. when decomposing a compound clip, all effects, gradings and settings should be kept and applied to the original clip in the timeline

2. the metadata could show the information of the containing clip. I know it’s difficult once we have more than one clip in it. But this could also be nice to toggle in a smart way.

3. thinking the second point even further would allow relinking as well to and from the clips.

4. In the new cut page, when source viewer is active, compound clips are not included in source reel.