Implement custom checkout (#487)

* Implement custom checkout core

* Fix elements on core

* Add files to providers

* Adapt providers

* Update types

* Update shopify file

* Format files

framework/local/api/endpoints/customer/address.ts

@@ -0,0 +1 @@
+export default function noopApi(...args: any[]): void {}

framework/local/api/endpoints/customer/card.ts

@@ -0,0 +1 @@
+export default function noopApi(...args: any[]): void {}