add dynamicRef/generic support for collections when openapi 3.1 is supported

today we implement collections as:

• BaseCollectionResponse (Odata next link field, etc...)
• BaseCounCollectionResponse (inherits from the previous, add the count field)
• A lot of Users/Groups/Sites/...Collection response (inherits from one of the previous, adds the value property)

With the advent of OpenAPI 3.1 support we could get rid of all the UsersCollectionResponse schemas (about 4k in v1) and make the base types generic.

Blocked awaiting OpenAPI v3.1 support