Please support setting temp path in setup.php

[goetzk]

A number of settings can be changed in ca before it has fully started, using it's setup entry point.
From my testing ca app/tmp location is needed before custom configuration is read meaning all sites need to able to write app/tmp.
It would be good if tmp could be set via a ca_temp which could then be configured as required.

Sorry for the short request, I can expand on it later if that will help.

[goetzk]

My changes to enable this suggestion are at https://github.com/medeopolis/providence/tree/customisable-temp-path and I'll be testing them in the coming days.

[goetzk]

As an update for the request, I have opened #1655 and tested it on dev/php8. It appears to be working correctly, but testing from others might be beneficial too.