GitLab

- 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

- removed proxy setup method
- reworked clone method

BREAKING CHANGE: method signature for cloneRepository changed