Feat(fulfillment): service provider registration + fulfillment management (#6524)

**What**
- Create the fulfillment manual package with a first iteration API 
- Create a new `AbstractFulfillmentProviderService` and `IFulfillmentProvider`
- Modify the module service interface to add new methods to manipulate the fulfillment and the communication with the external provider
  - create (no bulk)
  - cancel (no bulk)
  - update (no bulk)
  - list
  - listAndCount
  - retrieve
- Add new methods to the service provider service to include communication with the third party provider
  - get options
  - create
  - cancel
  - validate data
  - validate option
- Update/create interfaces and DTO's
- fix repository serializer to allow non entity to be passed without throwing
- split module tests into multiple files to simplify navigation
- Add integration tests to validate fulfillments manipulation and external provider loading + communication

FIXES CORE-1729
FIXES CORE-1785
FIXES CORE-1784
FIXES CORE-1766

packages/utils/src/dal/mikro-orm/utils.ts

@@ -148,11 +148,30 @@ export const mikroOrmSerializer = async <TOutput extends object>(
   options?: any
 ): Promise<TOutput> => {
   options ??= {}
+
+  const data_ = Array.isArray(data) ? data : [data]
+
+  const forSerialization: unknown[] = []
+  const notForSerialization: unknown[] = []
+
+  data_.forEach((object) => {
+    if (object.__meta) {
+      return forSerialization.push(object)
+    }
+
+    return notForSerialization.push(object)
+  })
+
   const { serialize } = await import("@mikro-orm/core")
-  const result = serialize(data, {
+  let result: any = serialize(forSerialization, {
     forceObject: true,
     populate: true,
     ...options,
-  })
-  return result as unknown as Promise<TOutput>
+  }) as TOutput[]
+
+  if (notForSerialization.length) {
+    result = result.concat(notForSerialization)
+  }
+
+  return Array.isArray(data) ? result : result[0]
 }

packages/utils/src/fulfillment/index.ts

@@ -1,2 +1,3 @@
 export * from "./geo-zone"
 export * from "./shipping-options"
+export * from "./provider"

packages/utils/src/fulfillment/provider.ts

@@ -0,0 +1,65 @@
+import { IFulfillmentProvider } from "@medusajs/types"
+
+export class AbstractFulfillmentProviderService
+  implements IFulfillmentProvider
+{
+  static identifier: string
+
+  static _isFulfillmentService = true
+
+  static isFulfillmentService(obj) {
+    return obj?.constructor?._isFulfillmentService
+  }
+
+  getIdentifier() {
+    return (this.constructor as any).identifier
+  }
+
+  async getFulfillmentOptions(): Promise<Record<string, unknown>[]> {
+    throw Error("getFulfillmentOptions must be overridden by the child class")
+  }
+
+  async validateFulfillmentData(optionData, data, context): Promise<any> {
+    throw Error("validateFulfillmentData must be overridden by the child class")
+  }
+
+  async validateOption(data): Promise<boolean> {
+    throw Error("validateOption must be overridden by the child class")
+  }
+
+  async canCalculate(data) {
+    throw Error("canCalculate must be overridden by the child class")
+  }
+
+  async calculatePrice(optionData, data, cart) {
+    throw Error("calculatePrice must be overridden by the child class")
+  }
+
+  async createFulfillment(data, items, order, fulfillment): Promise<any> {
+    throw Error("createFulfillment must be overridden by the child class")
+  }
+
+  async cancelFulfillment(fulfillment): Promise<any> {
+    throw Error("cancelFulfillment must be overridden by the child class")
+  }
+
+  async getFulfillmentDocuments(data) {
+    return []
+  }
+
+  async createReturnFulfillment(fromData): Promise<any> {
+    throw Error("createReturn must be overridden by the child class")
+  }
+
+  async getReturnDocuments(data) {
+    return []
+  }
+
+  async getShipmentDocuments(data) {
+    return []
+  }
+
+  async retrieveDocuments(fulfillmentData, documentType) {
+    throw Error("retrieveDocuments must be overridden by the child class")
+  }
+}