Set more suitable default memory limit in php.ini

[ralflang]

Provide either a fixed /etc/php/*/php.ini both for the PHP7 and PHP8 builds for web and cli SAPI or preferably an equivalent buildtime change of the respective setting. Raise the process memory limit to 512 MB. The default 128 MB are not suitable in some cases and lead to unexpected behaviour.

[ralflang]

I am currently trying to roll the php7 and php8 base images with increased memory. I use a conf.d snippet in hopes I can serve both apache2 and CLI with one file.