Deprecation of the www. subdomains

The reason for this deprecation is rather simple, we don’t want to keep too many subdomains around due to caching issues, traffic separation and SEO issues. We kept www. subdomains around because in certain countries they used to bypass country-specific bans/blocks of Derpibooru. However, we’ve learned that the countries in question recently started being able to access the normal site (without www.) without a VPN or a proxy, so there’s literally no reason to keep them around anymore.