docs: new section "Next Generation Repositories (NGR) support"

[lnielsen]

• What is COAR NGR?
• Supported:
  • COUNTER
  • Creative Commons Licenses
  • ETag
  • International Image Interoperability Framework
  • ORCID
  • OpenID Connect
  • Signposting
  • Sitemaps
  • Social Network Identities
• Planned:
  • ResourceSync
  • SUSHI
  • SWORD
• Unsupported (currently):
  • Activity Streams 2.0
  • HTTP Signatures
  • Linked Data Notifications
  • IPFS
  • Web Annotation Model and Protocol
  • WebID
  • WebID/TLS
  • Webmention
  • WebSub

[almereyda]

The content can easily be adapted from http://ngr.coar-repositories.org/ which is available at https://github.com/coar-repositories/ngr (without licence).