feat(types,modules-sdk): basic module setup for promotions (#5920)

RESOLVES CORE-1580

packages/promotion/src/initialize/index.ts

@@ -0,0 +1,27 @@
+import {
+  ExternalModuleDeclaration,
+  InternalModuleDeclaration,
+  MODULE_PACKAGE_NAMES,
+  MedusaModule,
+  Modules,
+} from "@medusajs/modules-sdk"
+import { IPromotionModuleService, ModulesSdkTypes } from "@medusajs/types"
+import { moduleDefinition } from "../module-definition"
+import { InitializeModuleInjectableDependencies } from "../types"
+
+export const initialize = async (
+  options?: ModulesSdkTypes.ModuleBootstrapDeclaration,
+  injectedDependencies?: InitializeModuleInjectableDependencies
+): Promise<IPromotionModuleService> => {
+  const loaded = await MedusaModule.bootstrap<IPromotionModuleService>({
+    moduleKey: Modules.PROMOTION,
+    defaultPath: MODULE_PACKAGE_NAMES[Modules.PROMOTION],
+    declaration: options as
+      | InternalModuleDeclaration
+      | ExternalModuleDeclaration,
+    injectedDependencies,
+    moduleExports: moduleDefinition,
+  })
+
+  return loaded[Modules.PROMOTION]
+}