feat(medusa, stock-location, inventory): Allow modules to integrate with core (#2997)

* feat: module shared resources

packages/medusa/src/interfaces/services/event-bus.ts

@@ -1,3 +1,6 @@
+import { EntityManager } from "typeorm"
+
 export interface IEventBusService {
   emit(event: string, data: any): Promise<void>
+  withTransaction(transactionManager?: EntityManager): this
 }