dvc dag showing status of stages

[ostromann]

There are several related issues regarding a feature like this both in DVC (#5369) as well as in Studio (#iterative/studio-support/issues/81, #iterative/studio-support/issues/59, #iterative/studio-support/issues/40). The general idea is that ´dvc dag´ should have a feature to also display the status of stages. Especially the mermaid markdown supports styling that can be used to enrich the DAG with additional information.

Things that could be of relevance to show:

1. A stage has run, has unmodified deps, unmodified outs and all of the data is pushed to the remote (This could be indicated in green)
2. A stage has run, has unmodified deps, unmodified outs, but the data is missing on the remote (Needs to call dvc push - Could be indicated in orange)
3. A stage has a modified command, dep or out and should be run with dvc repro (This could be indicated in red)

dvc status and dvc status -c delivers this kind of information as well, but one component is missing in my opinion.

4. A stage has upstream stage that have modified commands, deps or outs and it is uncertain if it would need to re-run or not (This could be indicated in grey)

[daavoo]

Related #7782

[ostromann]

Added a PR for my current solution. Would very much appreciate, if you could work it in somehow.