Improve licensing practices

We want all license metadata to be present and to be correct. We also need full accounting for it.

  • [x] https://www.it-cisq.org/software-bill-of-materials/index.htm
  • [ ] Use https://reuse.software/ in order to check licensing in source code.
    • [x] Use tmp branch for this experiment.
    • [x] https://reuse.software/tutorial/
      • [x] reuse init
      • [x] ~/.local/bin/reuse lint
    • [ ] Check this in daily CI for all repos. Just create the workflow for now. The actual license info will be fixed via the weekly test deployments task.
    • [x] The reuse-tool is licensed under the GPL-3. Is that a problem?
    • [x] Register main repo at: https://api.reuse.software/register
  • [x] Create licensing guidelines.
    • [x] Create documentation stating all licence checks, that should be done.
    • [x] Add REUSE to licensing guidelines.
  • [x] Document/link licensing overview in README. -> This is not relevant for now.
  • [x] Add Reuse to project file system standard and document, that its LICENSES folder is exceptional.
  • [x] When rendering CommonMark files, the licence info at the start of the file should be moved to the end of the file.
  • [ ] Improve licensing info on deployed website.
    • [ ] Licensing of images
    • [ ] List license of every page centrally.
    • [ ] Show license of every page on every page.
    • [x] Link to NOTICE.md and LICENSE.md.