Show a loader when making a request from the mod panel

[theyokohamalife]

Problem

When a user makes a request from the moderation panel, there isn't any indication that the request was made or completed.

Discussion

Success

When a user makes a request to approve, update, or reject a submission, a loader is shown until the request completes.

Implementation notes

Depending on the request that is being made, we may want the loader to say something like:
Approving submission..." Updating submission... Rejecting submission...`