CMS - add a link section to dataset semantics

[katilp]

To display the NANOAOD content HTML listing,

• add a link field to dataset_semantics in https://github.com/cernopendata/opendata.cern.ch/blob/master/cernopendata/jsonschemas/records/record-v1.0.0.json
• make NANO records display it in https://github.com/cernopendata/opendata.cern.ch/blob/master/cernopendata/templates/cernopendata_records_ui/records/record_detail.html

[katilp]

Adding a separate entry in record-v.1.0.0.json:

    "dataset_semantics_files": {
      "properties": {
        "html_doc": {
          "description": "Name of the dataset content description html file",
          "type": "string"
        },
        "json_doc": {
          "description": "Name of the dataset content description json file",
          "type": "string"
        }
      },
      "type": "object"
    },

A tentative display to be fixed to produce a proper link in record_details

    {% if record.dataset_semantics_files %}
    <div>
        <h2>Dataset semantics</h2>
        <p> Link to {{ record.dataset_semantics_files.html_doc }}</p>
    </div>
    {% endif %}

@tiborsimko These files are generated with the derived data records and are in outputs/docs of the cernopendata/data-curation#214

Do we place them under a separate directory e.g. /eos/opendata/cms/nano-docs/<recid>?