add dry run option?

[dmeliza]

It would be nice for users to be able to see how adding a resource would work without actually moving files. The only issue is that POSTing to the database is required for generating a new ID, and the API doesn't support the DELETE command that would undo the POST, nor would we want it to. The only real workaround I can see is for the API to have some endpoint for doing a dummy deposit.