feat: move create inventory to @medusajs/workflows (#5301)

**Why**
- We have some workflow-like flows in @medusajs/medusa. These should be moved over to the workflows package.
- Inventory Items <> Variant currently assume a 1-1 mapping. There should be support for a many-to-many mapping.

**What**
- PR introduces a feature flag for supporting many-to-many mappings for inventory and variants.
- Deletes legacy transaction handler in @medusajs/medusa.
- Adjusts existing createInventoryItems handler to remove dependency on variant data.

**Unkowns**
~~1. Couldn't find an existing test for the CreateProduct workflow. It should be tested that this still works as expected.~~
2. Have removed transaction managers as we should move to handling consistency through orchestration tooling. Are we ready for that?

integration-tests/plugins/__tests__/workflows/inventory/create-inventory-items.ts

@@ -0,0 +1,93 @@
+import path from "path"
+import { initDb, useDb } from "../../../../environment-helpers/use-db"
+import { bootstrapApp } from "../../../../environment-helpers/bootstrap-app"
+import {
+  createInventoryItems,
+  CreateInventoryItemActions,
+  pipe,
+} from "@medusajs/workflows"
+import { IInventoryService, WorkflowTypes } from "@medusajs/types"
+import { ModuleRegistrationName } from "@medusajs/modules-sdk"
+
+describe("CreateInventoryItem workflow", function () {
+  let medusaProcess
+  let medusaContainer
+
+  beforeAll(async () => {
+    const cwd = path.resolve(path.join(__dirname, "..", "..", ".."))
+    await initDb({ cwd } as any)
+    const { container } = await bootstrapApp({ cwd })
+    medusaContainer = container
+  })
+
+  afterAll(async () => {
+    const db = useDb()
+    await db.shutdown()
+
+    medusaProcess.kill()
+  })
+
+  it("should compensate all the invoke if something fails", async () => {
+    const workflow = createInventoryItems(medusaContainer)
+
+    workflow.appendAction(
+      "fail_step",
+      CreateInventoryItemActions.createInventoryItems,
+      {
+        invoke: pipe({}, async function failStep() {
+          throw new Error(`Failed`)
+        }),
+      },
+      {
+        noCompensation: true,
+      }
+    )
+
+    const input: WorkflowTypes.InventoryWorkflow.CreateInventoryItemsWorkflowInputDTO =
+      {
+        inventoryItems: [
+          {
+            sku: "TABLE_LEG",
+            description: "Table Leg",
+          },
+        ],
+      }
+
+    const { result, errors, transaction } = await workflow.run({
+      input,
+      context: {},
+      throwOnError: false,
+    })
+
+    expect(errors).toEqual([
+      {
+        action: "fail_step",
+        handlerType: "invoke",
+        error: new Error(`Failed`),
+      },
+    ])
+
+    expect(transaction.getState()).toEqual("reverted")
+
+    expect(result).toHaveLength(1)
+    expect(result[0].inventoryItem).toEqual(
+      expect.objectContaining({ id: expect.any(String) })
+    )
+
+    const inventoryService: IInventoryService = medusaContainer.resolve(
+      ModuleRegistrationName.INVENTORY
+    )
+
+    const [inventoryItems] = await inventoryService.listInventoryItems(
+      { id: result[0].inventoryItem.id },
+      { withDeleted: true }
+    )
+
+    expect(inventoryItems[0]).toEqual(
+      expect.objectContaining({
+        id: result[0].inventoryItem.id,
+        deleted_at: expect.any(Date),
+      })
+    )
+  })
+})