Draft: Pages settings and domain flow improvements

What does this MR do and why?

Describe in detail what your merge request does and why.

I was working on the Domain Verification MVC, which required that I configure and verify a Pages domain. I found the experience very confusing. For example, upon initially creating a domain I received an error that HTTPS-only was enabled and I needed to provide a certificate and key. I didn't need HTTPS for my test so I then tried to figure out how to disable HTTPS-only mode, but the setting wasn't exposed. After digging in to code I figured out the setting was only visible once a Pages site is already deployed.

The next issue I encountered was if I created a custom domain but haven't yet validated it and hadn't deployed pages. I wasn't able to see the domain in the pages settings. It appeared as if I had no domains. But they did exist and I could navigate directly to them.

These changes aim to expose the general Pages settings at all times and also allows listing existing domains so they're easily accessible. I believe this brings behavior more in line with how it was prior to !78276 (merged), but also still enabling that improved experience with the wizard.

Screenshots or screen recordings

Before

use_pipeline_wizard_for_pages disabled

Before it was not possible to get passed this point without successfully deploying a pages site. Only once a site is deployed would the domain list and settings be available

After

use_pipeline_wizard_for_pages disabled

use_pipeline_wizard_for_pages enabled

First visit redirects to wizard

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

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