ingest process for TileMatrixSet registry

[rob-metalinkage]

#109 is actually about making the content of an external repository visible through the definitions available from the def server.

Need to define a process to make github content available - noting direct access to github does not support correct MIME types, so the definitions server needs to check out and serve a working copy with correct MIME types, if these are linked to the normal locations for those mime types in other NamingAuthority content then no additional redirection rules should be required to make these accessible.
Normal forms (i.e. SKOS) view as TTL, RDF/XML should be generated so all expect formats are available.

[rob-metalinkage]

note the JSON-LD uplift process to generate the SKOS view from this content is required. If there is a conceptual model then contexts should refer to it, however we may only need to turn it to RDF and run a transform and extract to create a SKOS view ready to expose as a definition.

[rob-metalinkage]

hi - to process the new version we need to address a requirement to identify what concept scheme each concept lives in.

this can be done by either:
making it explicit via skos:inScheme, skos:topConcept and a narrower/broader hierarchy or by uri root matching

http://www.opengis.net/def/tms a skos:ConceptScheme ;

does not match

http://www.opengis.net/def/tilematrixset/OGC/1.0/WebMercatorQuad,

i guess we can add a rule that if exactly one concept scheme is defined then we will assume membership - but first lets check this content is actually correct..