5th Star suggestion: CORS compatibility

[yum-yab]

Using CORS compatibility for ontologies as the 5th star of archivo:

Proposed qualifying criteria for the 5th star:

• an ontology allows a CORS request when a preflight request was sent from at least two different domains.
• a CORS response allows to use a Content-Type header to preform content-negotiation in the browser RDF client.

As suggested in the forum.

[berezovskyi]

a CORS response allows to use a Content-Type header to preform content-negotiation in the browser RDF client.

Actually, I got this one wrong. We need it in our APIs because they are read/write, but generally you'd only need Accept header for this part of conneg and https://fetch.spec.whatwg.org/#cors-safelisted-request-header allows / and + by default.

[berezovskyi]

Also, suggested by @kurzum in another thread, it may be better to keep the number of passing checks separate from the number of stars awarded to keep it sane.