Refactor #5139 - leftovers subscribe_to_all_hostgroups

This functionality is replaced by simply creating a filter "view_hostgroups" , "unlimited" and assigning it to a role. This PR only cleans up the leftovers of it.
After the permission system migration, these values are irrelevant, so it doesn't matter what they return, true/false, they were used to authorize users to domains, hostgroups, and so on, the new system just disregards this. 

If you're using api/v1 and Foreman > 1.5 it'll just mean you'll get default values for these fields, so clients can't really make any use of these. If someone is using these fields in their clients well it's making a big mistake as these fields do not matter at all in Foreman and are never updated according to the authorization system.