Beta release (incl. Zenodo deposit) and installation on demo server

- [x] Add release procedure documentation (docs, changelog, tags) to README and CONTRIBUTING.md (see [here](https://github.com/codecheckers/ojs-codecheck?tab=readme-ov-file#creating-a-release))
- [ ] Have a working and running OJS instance hosted by the TU Dresden (depends on: https://github.com/codecheckers/check-pub/issues/18)
- [ ] install the codecheck plugin to this instance for the Beta/Demo release; add two journals, "../demo" and "/credit", the latter is not publicly listed
- [ ] add demo data to the plugin, see https://github.com/TIBHannover/geoMetadata/tree/main/testData for an example; add the demo data to the demonstration journal (see #45)
- [ ] add a `.zenodo.json` and deposit the release on Zenodo (in the CODECHECK community)