[Core] add caching for recursive variant checking

[dpfaffenbauer]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no

fixes #2519

[solverat]

@dpfaffenbauer That looks good to me! 👍 I just stumbled over an existing clear listener:

CoreShop/src/CoreShop/Bundle/ProductBundle/Resources/config/services.yml

Lines 117 to 122 in dd7aade

	CoreShop\Bundle\ProductBundle\EventListener\ClearCachedPriceRulesListener:
	tags:
	- { name: kernel.event_listener, event: coreshop.product_price_rule.post_save, method: clearCachedRules }
	- { name: kernel.event_listener, event: coreshop.product_specific_price_rule.post_save, method: clearCachedRules }
	- { name: kernel.event_listener, event: coreshop.product_price_rule.post_delete, method: clearCachedRules }
	- { name: kernel.event_listener, event: coreshop.product_specific_price_rule.post_delete, method: clearCachedRules }

Don't know if this should be consolidated or at least the new payment rule cleared should be added?

[dpfaffenbauer]

@solverat I am honestly not sure where that tag is set

[dpfaffenbauer]

@solverat just figured it out, that is not used anymore. I'll delete it