ISO19139 / Related directive / Add capability to filter on initiative types

[fxprunayre]

Related directive config allow to define a list of type of relation to load but in the case of associated resources (ie. siblings or aggregates in ISO19139 or ISO19115-3), it does not offer capability to filter on the type of resources (eg. sensor, models, ...) which you may want to display in specific sections.

Proposal: Add a new option which allows to filter on a property of the related resources.

eg.

      <div data-gn-related="md"
           data-types="siblings|associated"
           data-filter="associationType:upstreamData"
           data-title="Links"></div>