When the APCu extension is installed, Doctrine will automatically use it for metadata and query caches. This means a speedup for our applications since the Doctrine Entity metadata (mapping to the database) does not have to be parsed & processed on every request.

Acceptance criteria:

• APCu PHP extension is installed both on UAC and production system (using our infrastructure playbooks)
• Cache is automatically cleared on deployment (using our deployment playbooks in the respective code repos)

Notes:

• This ticket depends on T247746: Remove FundraisingStore from the Fundraising Operation Center and T247745: Reintegrate split store into FundraisingFrontend, because they'll use the Doctrine Setup class instead of FundraisingStore to set up the entity manager.
• The package name is php-apcu, the name is the same for all PHP versions.