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/core/medusa-test-utils/src/init-modules.ts

@@ -5,7 +5,7 @@ import {
 } from "@medusajs/types"
 import {
   ContainerRegistrationKeys,
-  ModulesSdkUtils,
+  createPgConnection,
   promiseAll,
 } from "@medusajs/utils"
 
@@ -41,7 +41,7 @@ export async function initModules({
 
   let shouldDestroyConnectionAutomatically = !sharedPgConnection
   if (!sharedPgConnection) {
-    sharedPgConnection = ModulesSdkUtils.createPgConnection({
+    sharedPgConnection = createPgConnection({
       clientUrl: databaseConfig.clientUrl,
       schema: databaseConfig.schema,
     })