Fixes #6211,BZ1102521 - Requiring a user to ping pulp_auth

It looks like the code didn't properly set User.current so Katello.pulp_server
was nil. This code checks for a user in the controller. Also, it handles the
case of no user by skipping the pulp_auth check which needs remote_id from a
user.
fixes #6197 - moving host/guests to virtual_host/virtual_guests

This corrects conflict with foreman host link

rubocop fix

spec test fix
fixes #6215 - do not pass full objects to rabl

fixes #6215 - return available_content to products node

fixed test
Merge pull request #4264 from thomasmckay/6197-host-guest

6197-host-guest - moving host/guests to virtual_host/virtual_guests
Merge pull request #4266 from thomasmckay/6215

fixes #6215 - do not pass full objects to rabl
Merge pull request #4265 from daviddavis/temp/20140613091921

Fixes #6211,BZ1102521 - Use hidden user's remote id to ping pulp_auth