DVC garbage collection

[dberenbaum]

It would be nice to have Studio automatically monitor and garbage collect my cloud DVC remote. For example, I could set up a policy in Studio to garbage collect any files:

• Created before [enter date]
  AND
• Not used in any [choose between commits/tags/branches]

Studio could run a job daily to garbage collect based on this policy.

Also, it would be nice to have some non-recurring option to select a bunch of commits to keep and garbage collect the rest.

[dberenbaum]

Another use case for this: if I delete experiments in Studio, it would be nice to also trigger garbage collection to remove the related data from the remote.