Smarter processing of `CI_ENVIRONMENT_URL`

We parse environment: url: and provide it to running scripts as CI_ENVIRONMENT_URL, but many times, scripts need that information as a hostname, not as a URL. We should provide CI_ENVIRONMENT_HOSTNAME as well. There's an open question what we should do with paths in the URL. Should they be dropped, or passed along in the _HOSTNAME even though technically they're not a hostname? Should we pass them as CI_ENVIRONMENT_PATH? Should we create a different variable for CI_ENVIRONMENT_HOSTNAME_AND_PATH? Is there a better word for that?

Also, having to specify the https:// in URLs is kinda annoying. Should we make that optional and implied, even though it's not a full URL without it?