* Replace filters with an extendibility API to hook into Cart and Checkout blocks
* Update docs
* Add a validate argument
* Add docs comments
* Add tests
* Add validation function
* Prefix validateElementOrString with __experimental
* Update experimental docs
* Typo
* Update comment
* Update JS docs
* Use an object for applyCheckoutFilter args
* Args doesn't need to be an object
* Wrap validation function execution in a try/catch block
* Only accept strings for the totalLabel filter
* Change applyCheckoutFilter signature
Albert Juhé Lluveras