Add Hostgroup API views Facet extenstion points
Facets can extend API responses for Host, but not Hostgroup.
- Fixes #31213 - hostgroup API facets extension point
Adds Facet extension points for Hostgroup API responses.
Refactor refresh for facets, to ensure all run just once.
Now the already registered entries are being run once the facet entry point is configured.
The hook is registered also on the entry point registration.
It should give us more clear API of the new facet entry poin registration.
- Refs #31213 - model specific definition iterrable
fixes an issue with an Model having access to general facet definitions (entries)
rather than it's own (model based entries) definitions.
- Refs #31213 - Add tests for API response with facets