Feat(auth): Rename authentication to auth (#6229)

**What**
- rename `authenticationModule` -> `authModule`

packages/auth/src/loaders/container.ts

@@ -0,0 +1,10 @@
+import { ModulesSdkUtils } from "@medusajs/utils"
+import * as ModuleModels from "@models"
+import * as ModuleRepositories from "@repositories"
+import * as ModuleServices from "@services"
+
+export default ModulesSdkUtils.moduleContainerLoaderFactory({
+  moduleModels: ModuleModels,
+  moduleRepositories: ModuleRepositories,
+  moduleServices: ModuleServices,
+})