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

.github/workflows/generate-preview-references.yml

@@ -60,6 +60,8 @@ jobs:
           base: "develop"
           title: "chore(docs): Updated API Reference (v2)"
           labels: "type: chore"
-          add-paths: www/apps/api-reference/specs
+          add-paths: |
+            www/apps/api-reference/specs
+            www/utils/generated/oas-output
           branch: "docs/generate-api-ref"
           branch-suffix: "timestamp"