recommend apache mpm_* mode based on php run mode in use (mod_php vs php-fpm)

[mahibi]

Recommend using mpm_event instead of mpm_prefork in the settings.

See also for talk:
https://github.com/nextcloud/spreed/blob/2832023ab6a51ed5b9510c9925bafbb9e33d18ed/src/components/AdminSettings/WebServerSetupChecks.vue#L123

[szaimen]

I still wonder if it is enough to just show it in the talk settings?