Absolute URLs now don't work in development

[jaredcwhite]

In Bridgetown 2.0 beta 2, an absolute URL might output as http://0.0.0.0:4000/2024/08/action-web-components/ which doesn't work as you can't directly connect to a 0.0.0.0 URL.

And in a related issue, we lost the helpful post-build localhost and IP address printouts in the console with the rack/puma refactorings, so we should make sure that's added back in.