Add a function to run a doc against the quality endpoint

[amoeba]

[drkrynstrng]

I think this is the mdq_run() function that was added to arcticdatautils:
https://github.com/NCEAS/arcticdatautils/blob/master/R/quality.R

Should it be moved here? It doesn't necessarily aid in authoring checks, but it does allow checking a metadata document against a production quality suite before uploading or updating. It can also be used with a number of quality suites, not just the Arctic Data Center suite.