feat: define link util (#7931)

* feat: define link util

* handle pluralized fieldAlias for isList

* serviceName ar reference

* finalize

* todo

* WIP

* finalize

* fix tests

* update typings

* fix Module

* linkable

* update errors

packages/modules/region/src/index.ts

@@ -1,9 +1,8 @@
-import { ModuleExports } from "@medusajs/types"
 import { RegionModuleService } from "./services"
 import loadDefaults from "./loaders/defaults"
+import { Module, Modules } from "@medusajs/utils"
 
-const moduleDefinition: ModuleExports = {
+export default Module(Modules.REGION, {
   service: RegionModuleService,
   loaders: [loadDefaults],
-}
-export default moduleDefinition
+})