Move away from Apache

[AffectedArc07]

If we can the forums, apache can be moved away from.

At the moment, we're kinda beholden to it

1. I enjoy .htaccess too much - sue me
2. I have a custom apache plugin that restricts access based on forum groups even for proxied sites - and we make heavy use of this for Kibana

However

1. I can live without this if I absolutely have to
2. I can recode this to work as an nginx plugin, maybe Not needed, nginxPM does this natively with authentik

[AffectedArc07]

Update 2026-09-02

Only 3[4] things are left on the old webserver:

1. forums
2. admin.php
   a. document.php that powers it
3. prs_api.php for the PRs page

Once 2(2a) & 3 are handled, we will be able to do a forums migration then take the old webserver out back.