Automate deleted Dandiset recovery

[waxlamp]

We have gone through a manual process for an accidentally deleted Dandiset recovery one time, at a user's request. This issue is about creating an automatic "undelete" process that a user can initiate within the appropriate grace period.

This issue will require some discussion to properly define its scope. For example, this might start out just as admin-only automations that can assist us with the task of Dandiset recovery. A deeper option would be a user-facing control to initiate and manage the process. The latter is clearly (much) more work, at a higher level of risk, hence why a discussion is needed.