Improve license metadata
The license is not clearly communicated in the project. This PR attempts to improve that. When I found some other long-hanging fruits with metadata, I fixed them as well.
The largest part of the work was making the project REUSE compliant and thereby also marking which files are under the MIT license and a different copyright holder.
Also we should reinstate proper CI testing before we engage in any changes.
Max, since there are 571 pending PRs I wonder if we should not review these first to avoid creating a merge conflict problem?
Looking at the PRs, most of them are version upgrades. But you are right, going through the list is a good idea. I'm fine with keeping this PR open for a while.