Fixes #5429,BZ1102296 - Showing hosts and keys for views

API Changes: https://github.com/Katello/katello/pull/4480
I tested out `custom_field Fields::Reference` but it only seems to show the content host name (which isn't consistent with the rest of the commands which show id or id + name). Is there something I have to do to show those fields? Also, what's the advantage of `custom_field Fields::Reference`?