Tiered Pricing Table for WooCommerce 7.1.0

* Fix: fatal error with cart upsell on the cart

* New: New integration section
* New: WPML multicurrency integration
* Update: update copy-once to copy for tiered pricing fields in wpml.config
* Fix: PHP 8.1+ notices
* Fix: Product add-ons integration. Case when taxes are enabled.
* Fix: Do not remove item from cart when quantity is below the minimum. Update the quantity instead.

* Fix: frontend JS script error
* New: Cache for variable products
* New: Advanced product options
* New: Quantity measurement