Fixes #38028 - Update smart proxy URI methods for load balancer setups

[jeremylenz]

What are the changes introduced in this pull request?

Goes with theforeman/foreman#10382

1. Update smart proxy methods so that provisioning can use correct URLs in sub-man config.
2. Update the "Registration details" card to properly show load-balanced smart proxies, and also add the "Registered to" value to match what is shown in Hammer.

For content sources that are behind a load balancer:

For non-load balanced content sources, the card will not show the load balancer info:

Considerations taken when implementing this change?

As always, "Smart Proxy" will be changed to "Capsule" downstream by foreman_theme_satellite.

What are the testing steps for this pull request?

Set up a load-balanced smart proxy with registration_url set to the fqdn of the load balancer, as outlined in the docs
Provision a host with the load balanced smart proxy set as the content source (?)
The host's "registered through" value should be that of the load balancer, not that of the smart proxy behind the load balancer

To test the UI changes without a load balancer, you can do

diff --git a/app/models/katello/concerns/smart_proxy_extensions.rb b/app/models/katello/concerns/smart_proxy_extensions.rb
index 0311b4422a..944c875997 100644
--- a/app/models/katello/concerns/smart_proxy_extensions.rb
+++ b/app/models/katello/concerns/smart_proxy_extensions.rb
@@ -138,6 +138,7 @@ module Katello
 
       def registration_host
         registration_url.host
+        pulp_primary? ? registration_url.host : "loadbalancer.example.com"
       end

[jeremylenz]

hopefully setting(SmartProxy::PULP3_FEATURE, 'content_app_url') doesn't contain any crucial information that would be lost by only using its path.

[jeremylenz]

@ianballou Would this url be different for a smart proxy that uses an external Pulp? Is that setup supported with load balanced smart proxies?

[jeremylenz]

I added the bare registration_url method here so that Foreman can do things to the URI object it returns, directly (e.g. using its path and port).