BREAKING CHANGE: removed lots of code, templates, etc

- creates tmp dir
- copies over the stored assignment repo
- clones student submission repo
- runs the image the prof specified in its assignment, mounting
    - the assignment repo
    - the subission repo
    - an empty folder expecting the result file to be in after container
        finished
- reads result file
- converts to moodle understandable instances
- returns result to moodle

BREAKING CHANGE: Gitea eliminated
BREAKING CHANGE: Jenkins eliminated
BREAKING CHANGE: expected file type changed from zip to text
BREAKING CHANGE: textfile has to conform new modocot URI
BREAKING CHANGE: no Jenkins pipe needed in submission repo
BREAKING CHANGE: no Dockerfile needed in submission repo

- defined modocot URI for unittests and submissions
- directly expect a textfile, not an archive
- store config file and local repo copy in persistent place,
    instead of using Gitea

BREAKING CHANGE: file to be uploaded changed from zip to text
BREAKING CHANGE: no longer uses Gitea