New issue labels for PROTEUS

[timlichtenberg]

I started to introduce a few new labels and categories to structure the code development.

First, I introduced priority level versions, so that we can generally better distinguish issues by the relevance (time criticality and general importance):
Priority 1: critical --> Priority level 1: highest priority – critical & fast
Priority 2: high --> Priority level 2: high time criticality or importance
Priority 3: standard --> Priority level 3: medium time criticality or importance
Priority 4: tbd --> Priority level 4: nice to have features and/or has some time

Please make use of these when creating or updating issues that not yet have one of these qualifiers. I started to introduce them as well to other repositories aside PROTEUS, so that we can make use of them in the PROTEUS Developer Roadmap.

In addition, I created a unified label for issues that I believe are necessary to be resolved before PROTEUS can be submitted as a JOSS publication (JOSS publication). Same here, please use this label if an issue clearly needs to be resolved before the PROTEUS method paper can be submitted.

Finally, I create a new column JOSS publication, which bundles the issues with the same label for better visibility during our meetings.

If you have suggestions or additions for labels or sorting, please mention them here.