Enhance multi ontology support

Description of the issue

Since we first introduced the OEO and the integration into the OEP we now have multiple ontologies in the Open Energy Family. Currently it is already possible to "host" multiple ontologies on the OEP but some features are not flexible enough.

The oeo-viewer is currently specific to the OEO. Since we now implemented the OLS based TS service offered to the public by the TIB we can easily implement other ontologies if they are available on the TIB-TS.

Ideas of solution

First (@jh-RLI )

• Provide the access to all additional ontologies via the OEP´s ontology overview page

Then

• Notice the TIB to include the new ontologies
• Enhance the oeo viewer
• Check what modification the TSS "search and filter" widget
• Provide a UI to the user to select the ontology, probably using a TSS widget

Workflow checklist

• I am aware of the workflow in
  CONTRIBUTING.md