Management API: implement a restricted "get-all" endpoint

[paullatzelsperger]

Feature Request

All Mangement API endpoints should provide a (restricted) "get-all" endpoint, that returns the entire Collection of entities.

Which Areas Would Be Affected?

All Managment APIs

Why Is the Feature Desired?

This is useful for management operations and for setting up test/demo environemnts.

Solution Proposal

add a endpoint that is restricted to the "admin" role, and accepts a QuerySpec

@GET
public Collection<SomeEntity> getAllEntities(){
   //...
}