feat: write REST API endpoint to create step

packages/backend/test/mocks/rest/api/v1/flows/create-step.js

@@ -0,0 +1,26 @@
+const createStepMock = async (step) => {
+  const data = {
+    id: step.id,
+    type: step.type || 'action',
+    key: step.key || null,
+    appKey: step.appKey || null,
+    iconUrl: step.iconUrl || null,
+    webhookUrl: step.webhookUrl || null,
+    status: step.status || 'incomplete',
+    position: step.position,
+    parameters: step.parameters || {},
+  };
+
+  return {
+    data,
+    meta: {
+      type: 'Step',
+      count: 1,
+      isArray: false,
+      currentPage: null,
+      totalPages: null,
+    },
+  };
+};
+
+export default createStepMock;