feat(dashboard): basic Order UI (#7225)

**WHAT**
- rudimentary list and details pages
- fix Order<>Promotion link
- fix Order<>SalesChannel link

**NOTE**
- displaying basic info since we don't have Fulfillments & Payments linked ATM
- `disaply_id` needs to be added to order
- `tax_rate` needs to be added to order

---


https://github.com/medusajs/medusa/assets/16856471/cd4e98c7-345e-4193-8c1e-ad4ed1584993



Co-authored-by: Carlos R. L. Rodrigues <37986729+carlos-r-l-rodrigues@users.noreply.github.com>

packages/core/modules-sdk/src/medusa-app.ts

@@ -175,7 +175,13 @@ function isMedusaModule(mod) {
 }
 
 function cleanAndMergeSchema(loadedSchema) {
-  const { schema: cleanedSchema, notFound } = cleanGraphQLSchema(loadedSchema)
+  const defaultMedusaSchema = `
+    scalar DateTime
+    scalar JSON
+  `
+  const { schema: cleanedSchema, notFound } = cleanGraphQLSchema(
+    defaultMedusaSchema + loadedSchema
+  )
   const mergedSchema = mergeTypeDefs(cleanedSchema)
   return { schema: makeExecutableSchema({ typeDefs: mergedSchema }), notFound }
 }