FIX: web.ssl.template compat with latest core

[davidtaylorhq]

discourse/discourse@649505d added some new content between listen 80; and gzip on;, which broke these replacements.

This commit reorders & updates the replacements so that they should work reliably with versions of core before and after that change.

• Move the /server.+{/ replacement to the end, so that it doesn't introduce a duplicate listen 80; which will get in the way of the other replacements
• Update the listen 80; gzip on; replacement to just look for listen 80;
• Update the listen 80;\s+listen \[::\]:80; gzip onl replacement to just listen 80;\s+listen \[::\]:80;
• Swap those two around, so that only one of them can ever run

[Firefishy]

The final server block listen 80; used for the redirect isn't enabled for IPv6 regardless of enabling web.ssl.template.yml
I'm don't see an issue just unconditionally turning on IPv6 listening for at least this block.