docs: add documentation for migration generate cli tool (#8128)

* docs: add documentation for migration generate cli tool

* changed migrations details in marketplace recipe

* added generated oas files to action

* vale + lint fixes

* don't import from src in medusa-config.js

* fix generate command in recipe

* fix module name

www/apps/resources/app/commerce-modules/order/page.mdx

@@ -74,7 +74,7 @@ const orderReturn = await orderModuleService.createReturn({
   items: [{
     id: "orditem_123",
     quantity: 1,
-  }]
+  }],
 })
 ```
 

www/apps/resources/app/commerce-modules/order/promotion-adjustments/page.mdx

@@ -102,7 +102,7 @@ const actions = await promotionModuleService.computeActions(
     items: lineItemAdjustments,
     shipping_methods: shippingMethodAdjustments,
     // TODO infer from cart or region
-    currency_code: "usd"
+    currency_code: "usd",
   }
 )
 ```