Create minified version of json export

[kevingranade]

dialogger json entities are rather verbose, we need an export option to trim them down to just the pieces that dda cares about.

We should keep the verbose version though so people can save their work without losing layout.

[kevingranade]

This is partially implemented already by the function gameData()/exportGameFile().
Upstream dialogger has the concept of a "complete" dialogue data file that has all the metadata jointJS needs, and an "export" with just the game data. The problem with this approach is you can't re-create the "complete" data from a game export, which is what we are going to want to do.
In order to support this we will need to deserialize the minimized nodes and then add the extra metadata needed by the gui.