GitLab

reworked pipeline to suit all branches

This pulls, builds and publishes now for every branch on the repo
Tag used is the branch name

if the commit the pipeline runs matches the format [0-9]+.[0-9]+.[0-9]+
the release stage is run additionally, which pushs the built image
additionally with the tags 'latest' and the tag.

On Jenkins the old Pipeline configurations are disabled and replaced by
a multibranch pipeline configuration

- based on openjdk:11-jre-slim instead of a base system and
    installing java manually
- removed git installation, we use a maven library for this
    no system installed git needed for anything
- removed this damn proxy env vars
    they have nothing to do baked into an docker image!!
- removed junit downloads
    not needed in backend. The testrunners are responsible
    for what they need
- removed setting of a specific profile
    in prod always the default one should be active,
    use a different profile on your dev machine which you
    DO NOT commit

BREAKING CHANGE: pom version bump to 2.0.0

BREAKING CHANGE: serializer def for Failure and Diagnostics removed

BREAKING CHANGE: removed lots of code, templates, etc

tests have to be re-written, preferrably with Mockito

- 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

the previously deleted set proxy from JGitUtil was just...meh

This checks if we got a proxy set in the properties file
Additionally the user can provide a list of not-proxy hosts.
This setup will then check, if a proxy is available and if so,
make sure it only gets used if the uri is not on the not-proxy list.

Moodle needs this structure to read the information to show.
What model to finally agree on has to be discussed later

this component initializes an DockerClient on startup,
then provides a method to run an container with an given image String
and n given Bind-mounts.
This method waits for this container to finish before returning,
so don't call any services that should just be started and left alone!

For this the library github-java-docker is used:
https://github.com/docker-java/docker-java

For this to work, the container this is run in obviously needs
access to the docker socket

- 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