Oqp updates

This PR will create GeoNode maps for the isc, ghec and gaf layers. It also update the topic categories with some sample categories as a proof of concept. The final topic categories still need to be defined.

When installed, the fixtures should add a isc, ghec and gaf maps to /maps/
@bwyss also this is different from current master. It's part of this PR or it will be part of a separate PR?