DTS <-> EMSL info

[jeff-cohere]

External metadata API: https://api.emsl.pnnl.gov/external/

There's also an EMSL Analysis API that should be fluffed in the next week or two.

EMSL thinks of things in terms of projects, datasets, and files. A project has one or more associated datasets (and umbrella metadata), and a dataset consists of one or more files. So far, it looks "topologically" similar to other orgs we've dealt with.