fix(medusa,js-sdk,types): Add basic draft order operations to js-sdk (#11514)

**What**
- Exposes `sdk.admin.draftOrder.create/update/retrieve/list` functions from the js-sdk
- Implements the necessary types in the types package.
- Adds missing endpoints to admin API.

integration-tests/http/__tests__/draft-order/admin/draft-order.spec.ts

@@ -0,0 +1,106 @@
+import { medusaIntegrationTestRunner } from "@medusajs/test-utils"
+import { HttpTypes } from "@medusajs/types"
+import { ModuleRegistrationName } from "@medusajs/utils"
+import {
+  adminHeaders,
+  createAdminUser,
+} from "../../../../helpers/create-admin-user"
+import { setupTaxStructure } from "../../../../modules/__tests__/fixtures"
+
+jest.setTimeout(300000)
+
+medusaIntegrationTestRunner({
+  testSuite: ({ dbConnection, getContainer, api }) => {
+    let region: HttpTypes.AdminRegion
+    let testDraftOrder: HttpTypes.AdminDraftOrder
+
+    beforeEach(async () => {
+      const container = getContainer()
+
+      await setupTaxStructure(container.resolve(ModuleRegistrationName.TAX))
+      await createAdminUser(dbConnection, adminHeaders, container)
+
+      region = (
+        await api.post(
+          `/admin/regions`,
+          {
+            name: "USA",
+            currency_code: "usd",
+            countries: ["US"],
+          },
+          adminHeaders
+        )
+      ).data.region
+
+      testDraftOrder = (
+        await api.post(
+          "/admin/draft-orders",
+          { email: "test@test.com", region_id: region.id },
+          adminHeaders
+        )
+      ).data.draft_order
+    })
+
+    describe("GET /draft-orders", () => {
+      it("should get a list of draft orders", async () => {
+        const response = await api.get("/admin/draft-orders", adminHeaders)
+
+        expect(response.status).toBe(200)
+        expect(response.data.draft_orders).toBeDefined()
+        expect(response.data.draft_orders.length).toBe(1)
+        expect(response.data.draft_orders).toEqual(
+          expect.arrayContaining([
+            expect.objectContaining({
+              email: "test@test.com",
+            }),
+          ])
+        )
+      })
+    })
+
+    describe("POST /draft-orders", () => {
+      it("should create a draft order", async () => {
+        const response = await api.post(
+          "/admin/draft-orders",
+          {
+            email: "test2@test.com",
+            region_id: region.id,
+          },
+          adminHeaders
+        )
+
+        expect(response.status).toBe(200)
+        expect(response.data.draft_order.email).toBe("test2@test.com")
+        expect(response.data.draft_order.region_id).toBe(region.id)
+      })
+    })
+
+    describe("GET /draft-orders/:id", () => {
+      it("should get a draft order", async () => {
+        const response = await api.get(
+          `/admin/draft-orders/${testDraftOrder.id}`,
+          adminHeaders
+        )
+
+        expect(response.status).toBe(200)
+        expect(response.data.draft_order.email).toBe("test@test.com")
+        expect(response.data.draft_order.region_id).toBe(region.id)
+      })
+    })
+
+    describe("POST /draft-orders/:id", () => {
+      it("should update a draft order", async () => {
+        const response = await api.post(
+          `/admin/draft-orders/${testDraftOrder.id}`,
+          {
+            email: "test_new@test.com",
+          },
+          adminHeaders
+        )
+
+        expect(response.status).toBe(200)
+        expect(response.data.draft_order.email).toBe("test_new@test.com")
+      })
+    })
+  },
+})