Fix/same submission

[cyfml]

1. fixed same submission problem which leads Comparision-Viewer broken.
2. fixed issue: The folder in the results holding the submission files should be renamed from "submissions" to "files", and report-viewer also supports old version of Jplag. (e.g. submissions in zip file).
3. Enhancement:

• where the files are dropped should contain a line of text that states that no files get uploaded anywhere
• The code comparison view always shows "submission 1" and "submission 2", but should show the names. But not if the names are hidden.
• In the code comparison view, the left sidebar should be visible by default

[tsaglam]

You should only touch the report generation here, so do not change the pipeline before that step. You changed:

[cyfml]

Now, report-viewer supports old version of Jplag. I also find a bug in the previous PR. This bug is: if root name or sub directory is also called "submissions". The Comparison view will not be broken but show not full path, then it influences the highlighting.
Previous one seems a coincidental, now i fixed this problem.

[tsaglam]

Review for the Java changes, I found just one small thing.

[sebinside]

Besides this change, I have nothing to complain. I'm not happy with the complexity of the extractFileNameWithFullPath function but have no better solution. In my testing, everything worked fine. Can be merged after the small change mentioned above.

[cyfml]

@sebinside Yes. The complexity of the extractFileNameWithFullPath function is pretty bad. No better solution because we need support old Jplag. I will change this problem mentioned above in 10 minutes.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

87.5% Coverage
0.0% Duplication

[cyfml]

@tsaglam @sebinside I suggest, it's better to change the name of PR to "Fix/same submission". Same root problem was postponed.

[sebinside]

Thank you @cyfml, I just merged this PR and updated issue #710. I also added a new strange bug that I discovered while testing (also prior to this PR). Maybe you can also find a solution to this.