JSON interface

[avirshup]

Replace current interface scheme with JSON serialization and deserialization. This should make it much easier to do interface development, especially for python packages, and will make the docker images much more lightweight.

The idea would be that MDT writes a JSON file that describes the molecule and the calculation needed. The "interface routine" then generates an input file (or equivalent) for program being used, and parses its output back into JSON.

This is quite possibly related to the establishment of a new standard, so it does require some thought and consideration, and ideally collaboration with other projects (e.g., MDAnalysis/mdanalysis#643)

[avirshup]

This is heavily related to the alchemistry/fileformat project (although not NECESSARILY identical)

[avirshup]

Also, this will be required for upcoming database-based projects

[avirshup]

Closing for now. This will be driven by MST requirements if at all.