Deliver comprehensive metadata in GNAF landing pages

[dr-shorthair]

Metadata for GNAF should be made available for inspection and harvesting through the expected modes:

• as RDF through the 'alternates' view
• as RDF through content-negotiation-by-profile
• embedded in the landingpage header as JSON in a Githubissues.
• Githubissues is a development platform for aggregating issues.