Cover cooperations and community projects in data model

[acka47]

Currently, we have no way to describe cooperations (e.g. OERSI) or community projects (lrmi-profile) or community products (Metafacture, SkoHub) as such. Here is some of the information that needs to be covered by adding such an approach:

• cooperating/collaborating institution
• individual project/product members from the cooperating institution
• start/end date of the cooperation

See also the hbz's page on cooperations: https://www.hbz-nrw.de/ueber-uns/kooperationen