No longer forces the creation of new contact handles on each domain registration
Now uses the Admin/Billing/Tech contact as configured in WHMCS. The "Use Clients Details" setting in WHMCS defines what we get as admin contact in $params. If the option is selected, it will be the same as the owner and the API will return the owner handle.
Fixed domain registration for .swiss domains, as they need to use AddDomainApplication instead of AddDomain