knowledge: slugify and flag to access rest api
- Covers all possible rest api urls and returns "not allowed" if it's not implemented.
- Adds a new field slug in knowledge and a mechanism to automatically generate it.
- Uses the slug as key in REST API instead of id.
- Adds a new field is_api_accessible to allow disabling REST API access to a mapping. (closes #2686)
Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
Co-authored-by: Jiri Kuncar <jiri.kuncar@cern.ch>