Should be enough to (1) talk to the Java API and (2) provide
a JSON API for the world.

This is really just experimental. MMT should be integrated directly
w/o JSON if possible to avoid nonsensical serialization.

Honestly Play is way too much for what I need. I just need
a simple JSON endpoint.

- I'll need some REST endpoint for the data

- GrahDB uses RDF4J -> JVM language prefered

- Let's try out Play. It works w/ Scala and Java.

- code goes into /src

- prose in /doc

- /experimental is a playground