chore: reorganize docs apps (#7228)

* reorganize docs apps

* add README

* fix directory

* add condition for old docs

www/apps/resources/app/commerce-modules/fulfillment/fulfillment-provider/page.mdx

@@ -0,0 +1,25 @@
+export const metadata = {
+  title: `Fulfillment Provider`,
+}
+
+# {metadata.title}
+
+In this document, you’ll learn what a fulfillment provider is.
+
+## What’s a Fulfillment Provider?
+
+A fulfillment provider implements the functionality of fulfilling items, typically using a third-party integration. It’s represented by the `FulfillmentProvider` data model.
+
+---
+
+## How to Create a Fulfillment Provider?
+
+A fulfillment provider is a TypeScript or JavaScript class that extends the `AbstractFulfillmentProviderService` class imported from `@medusajs/utils`. You can create it part of your Medusa application codebase, in a plugin, or in a provider module.
+
+---
+
+## Configure Fulfillment Providers
+
+The Fulfillment Module accepts a `providers` option that allows you to register providers in your application. When the Medusa application starts, it registers these modules and adds records of the `FulfillmentProvider` for them.
+
+Learn more about the `providers` option in [this documentation](../module-options/page.mdx).