Remove PHP APC support and APC references
Summary:
APC saw its last release in 2012.
It has been discontinued as PHP 5.5+ includes OpCache.
It has been superseded by APCu for object caching.
See https://pecl.php.net/package-info.php?package=APC
Phorge requires PHP 7.2.
Thus remove any references to APC.
Also note that "If APCu is installed, it reports that APC is installed" does not hold true anymore: In PHP 8.3, "php -m" correctly reports "apcu".
Test Plan:
* Make sure APCU is not installed, see `PHP Extension "APCu" Not Installed" under "Unresolved Setup Issues" as an admin
* Apply patch, still see same issue listed.
* Install `php-pecl-apcu` package on Fedora system; see that now the issue is not listed anymore under "Unresolved Setup Issues"
Reviewers: O1 Blessed Committers, valerio.bozzolan
Reviewed By: O1 Blessed Committers, valerio.bozzolan
Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno
Differential Revision: https://we.phorge.it/D25950