Prod fixes

[Nealium104]

Three main fixes.

1. Models were assigning variables to classes without declaring them first. PHP 8.2+ has deprecated this behavior. I declared each as public properties to address the issue.
2. Errors like the one in point 1 were printing in production. The php image we use provides some php.ini files with reasonable defaults for both production and dev. I include them in the correct stages in the Dockerfile.
3. Hardcoded paths were pushing users around to real production (https://exploreuk.uky.edu/) instead of our current "fake prod" (euk.ukpdp.org). Keeping with 12 factor, I made paths relative to the current server (whichever that may be).