Upgrade base box and stacks for Trixie

This probably should be the banner issue for a vagrant-spk 1.3 release. We need to validate Sandstorm installs well on Debian Trixie and any modifications needed to setup to get there, update the stacks to use the correct versions of PHP, MySQL, etc. for Trixie, and then test our LEMP and UWSGI stacks at minimum using their test apps to validate this works.