Move all testcase related files to TestCases?

[bigfooted]

I propose to move all testcase related files to this repository. That means moving the config files from the SU2 repository to this repository. I think that will make it easier to:

1. see if all files for the testcase are present (cfg + su2 file at the very least)
2. test if the case works because all files to run are present.

I'd like to hear your opinion.

[pcarruscag]

A lot of people don't get notified for this Repo.

I find it convenient to have reference files for files diffs in the code repo, less hassle when updates are required and file diffs break more easily than the other tests because there is 0 tolerance.

cfg + su2 + restart sounds like a good idea to move to testcases

[pcarruscag]

I remembered something, the version number in the testcase configs is updated automatically by a github action, we would need to setup something like that for this repo as well.

[bigfooted]

do you know how that works?