Updates and Optimizations

[brian]

Updated to PHP 7.4... more speed.

Also optimized SSL configuration to ensure only modern security schemes are allowed. No TLS v1.3, though... my OS build doesn't fully support a recent enough version of OpenSSL.

The "pretty urls" were dropped from Links, Gallery, and Forum. No one really sees URLs anymore, and it was just another action slowing down the site.

Since the previous update, I also moved to Brotli compression over gzip (gzip still supported where needed). It was another little performance boost.