Add Java support for suite files + test suites

[benjaminkostiuk]

Similar to #6, since it was closed with the addition of Haskell support.
Same procedure should work great, my only concern is really the Docker image size. I have Python down to 50mb, it would be nice to keep the Java image under 200 mb if possible.

[OZoneGuy]

Hey, I am getting back to this issue. One thing I wanted your feedback on is how to include the JUnit jar. I can either bake it into the image, download it and place it during building, or mount it. The latter seems like the better idea, but the issue being is how to copy it. Unless we want to add special code in the Java case that specifically copies the jar into the WORKDIR I don't see a good way of doing it.

I suppose what is also relevant is if other jar files are required for assignments. But I suppose we can handle that in a later iteration?...

I will start with the mounting approach and see where it goes, since it looks like the most time-consuming.

[benjaminkostiuk]

Sure whatever you think works best! I'm not against baking it into the image itself if it's small enough considering we won't be building images on every test case once I refactor the process.