Description:

This enables support for generating "enum" fields for selected queryables. There is also now a concept of optional queryable parameters - so it's possible to indicate enum fields without requiring that field to be present in all collections. This enum generation is very efficient as it's basically an index-only scan.

    "platform": {
      "description": "Satellite platform identifier",
      "title": "Platform",
      "type": "string",
      "enum": [
        "sentinel-2a"
      ]
    },

Other small changes include adding the previously missing get_items_mapping abstract to the base database logic. I also got confused by the existence of "OS_HOST" and "OS_PORT" variables in the Makefile which appear to be unused, so I simply removed them too.

PR Checklist:

• Code is formatted and linted (run pre-commit run --all-files)
• Tests pass (run make test)
• Documentation has been updated to reflect changes, if applicable
• Changes are added to the changelog