Expand dcm admin apis

[patrick_digan]

The dcm admin apis look promising. I would love if they could add put endpoints for sharing/execution and sharing/collaboration for admins. There is already a delete command for those two endpoints

[TheCoffeeDude]

This needs to be done. A gallery admin should be able to impersonate a user or perform all API requests on a user's behalf, especially when it's related to DCM.

[patrick_digan]

I had to send detailed instructions to show a user how to do the sharing/collaboration. It would have been easier for all involved if I could have just done it via API. We leverage many of the other endpoints, so this would be a nice add.