Remove Software/contentType (duplicative)

[bact]

• Update the Core/Properties/contentType.md with wording from Software/Properties/contentType.md, adjusted to accommodate both Element and Property
• Update Core/Datatypes/MediaType.md to accommodate both Element and Property, also add string examples
• Remove Software/Properties/contentType.md file
• Update Software/Classes/File.md to refer to /Core/contentType instead of contentType
• Update examples: file1.json and spdx_document2.json

This should resolve #781

[goneall]

LGTM - Thanks @bact

[goneall]

@JPEWdev - This would be a breaking change for existing 3.0.0 users. We're thinking of merging this into 3.0.1 - would this be a problem for your Yocto work?

[JPEWdev]

No, we aren't using that field. Is it possible to "hide" it in the spec, but leave it in the RDF so it's backward compatible maybe?

[goneall]

No, we aren't using that field. Is it possible to "hide" it in the spec, but leave it in the RDF so it's backward compatible maybe?

@JPEWdev - good to know.

For the RDF, we could keep the Software/contentType and use the owl:sameAs to associate it with the core/contentType. This would imply a bit of a hack to the spec parser to capture this - or a more extensive change to the markdown spec and the spec parser.

My opinion is if we get this changed quickly and release 3.0.1 with the changes, it won't impact many folks since we're in the early phases of 3.0 adoption.

I'm going to go ahead and merge this change.

@zvr if you have time - feel free to update the spec parser.