Define Feature Catalogue relations in metadata xml

[josegar74]

In actual implementation Feature Catalogue relations are stored only in the database (relations table).

This enhancement stores the relation in metadata xml, keeping the storage in database for backwards compatibility.

The relation is stored like:

<gmd:featureCatalogueCitation uuidref="22a7c5a0-3bea-4e53-9356-83d27d333cd8" xlink:href="http://localhost:8080/geonetwork/srv/en/metadata.show?uuid=22a7c5a0-3bea-4e53-9356-83d27d333cd8"/>

As CSW doesn't manage the iso19110 records in the xlink:ref url is use the metadata.show service instead.

Attached patch to review.

[fxp]

I would suggest a minor change (to be discussed) for the xlink:href URL:

• option 1: at least, point to a more generic URL ​http://localhost:8080/geonetwork/?uuid=22a7c5a0-3bea-4e53-9356-83d27d333cd8 which will work with both classic and new GUI.
• option 2: or point to a CSW GetRecordsById (after applying #723 which will add support for ISO19110 in ISO format in the output). This method also has the advantage to point to an XML document and not an HTML page like the srv:operatesOn/@xlink:href to link datasets and services.

[josegar74]

option 2 seem the best to me.