Improve conditions for review

[acka47]

I agreed to take over a reviewer role for changes to the GND ontology and, thus far, have reviewed two PRs. Generally, the review process would be much improved for me if

1. the ontology was maintained in Turtle not RDF/XML format
2. there was an automatic build of the HTML page based on the dev branch.

I am afraid, 1.) might not be straightforward to implement (but maybe I am wrong?). 2.) might easily be setup with a GitHub Actions deployment to GitHub pages. For this, we should add the scripts to the repo that build the HTML which makes sense anyway.

[thoffma]

Yes, you're right. I haven't been happy with the RDF/XML format for a while either. I'll take a look at what a change would affect.
For 2.) I think we can implement a build process.