also some quality of life ui improvements

Also removed a bunch of unnecessary code and extracted the test runner into https://gitlab.gwdg.de/grady-corp/grady-test-runner

blub

Also extended existing frontend tests for feedback creation.
In order to fix routing, partially refactored Subscription Vuex module #145

corrected test

Using multiprocessing.Lock to synchronize access to creation of Assignment

fixes #130

Tested with the following piece of code which should hava all edge cases. Works fine :

// should not be commented out
char c = '/*';
String s = "/* some stupid stuff */";

long test(REPLACED k){ /* only this should be commented out */
    if(REPLACED)
        return REPLACED;
    if(REPLACED)
        return REPLACED;
    /* this should be commented out
    if(REPLACED){
        if(REPLACED)
            return REPLACED;
        if(REPLACED)
            return (REPLACED);
    }
   */ this should not
    return 0;
}

fixes #135

Every branch shares the same dev-image and dev-image-base used for caching during the build image step.
On master, only tag commits are built and the image has the tag number

fixes #137

For now, every occurence of "student/s" that is visible to the user has been renamed to "participant". We should however think about how we adress the naming in the future.

fixes #133

At the moment the staging server is kinda broken and the functional tests already ensure that the app is not completely broken

Also, the student is not greeted with the anonimised name anymore

fixes #131