Allow setting DID and Ext with SCIM endpoint at creation time

Allow the SCIM source to pass the phoneNumbers of type work for DID and other for extension at create time to select which unassigned extension to use and set the extension number.

The phoneNumbers parameter exists and can be set, but does nothing on creation. It would be great to set the numbers in the source directory and have the process automatically select the correct unassigned extension if available based on the DID provided. The creation process could also set the extension number to the value provided. These are the fields that are returned everywhere else for existing users.