feat: Add skeleton for api key module (#6451)

Adds a module skeleton for the API Key module.
Implementation of functionalities will follow in separate PRs

packages/api-key/src/index.ts

@@ -0,0 +1,14 @@
+import { moduleDefinition } from "./module-definition"
+import { initializeFactory, Modules } from "@medusajs/modules-sdk"
+
+export * from "./types"
+export * from "./models"
+export * from "./services"
+
+export const initialize = initializeFactory({
+  moduleName: Modules.API_KEY,
+  moduleDefinition,
+})
+export const runMigrations = moduleDefinition.runMigrations
+export const revertMigration = moduleDefinition.revertMigration
+export default moduleDefinition