107 move systemkind to system capabilities

[dr-shorthair]

I've taken Alex's proposal and moved the classes, properties and related axioms into the System Capabilities extension module.

Preview: https://raw.githack.com/w3c/sdw-sosa-ssn/107-move-systemkind-to-system-capabilities/ssn/index.html#System-capabilities

[alexrobin]

I'm fine with this but could we just use the ssn namespace (http://www.w3.org/ns/ssn/) for the capabilities module (instead of the old ssn-system, http://www.w3.org/ns/ssn/systems) now that we moved pretty much everything else to sosa?

And deprecate concepts in ssn-system just like we did for the ssn concepts we moved to sosa?

[dr-shorthair]

@alexrobin interesting proposal. However, I'm not sure it works -

We 'emptied out' the ssn: ns - the terms that were in there are now tagged 'deprecated'.
The SSN module now only houses the axiomatization of the SOSA modules - as in the previous version.

The plan is that dereferencing http://www.w3.org/ns/ssn/ should get an ontology that supports everything that the previous edition did (the deprecated terms are still quietly imported), though it will also import additional terms in the sosa: ns.

So I think it would be confusing to make ssn: do double duty, also housing the System Capabilities terms.

[dr-shorthair]

Update team agreed not to introduce a specific SystemKind class.