[Site tech] IPv6 support

With ARIN having run out of IPv4 addresses it would be nice to see the site support IPv6. It may also affect performance on mobile which seems to be a quite popular way to access websites these days.

While it's not essential right now it is a nice method of future proofing & should be quick to implement[1] at this stage if your provider supports it.

[1] I believe you'd simply have to configure Apache to bind to both IPv4 & IPv6 addresses and add a relevant AAAA DNS record. This is unless your codebase makes use of IP addresses somehow, then it's a bigger project.