Move FeatureCollection download from STAC to OGC Features

[ThorodanBrom]

• https://docs.ogc.org/is/17-069r4/17-069r4.html#_link_relations
• Add link to OGC features /collections/<collection-id>
• Rename the stac_collections_assets to something else that only hosts feature 'enclosures'/assets
• Update the STAC APIs to stop regarding any OGC collections as a STAC collection
  • Only 'real' STAC collection e.g. (collection_type = STAC)
• Update feature CollectionOnboarding process
  • stac_collections_assets
• Maybe update the spec generation for Features

Cat and Canvas

• Make sure we keep them in loop about these changes

[ThorodanBrom]

Do we need to have a new endpoint/enclosure/<id> URL?