docs: oas (#197)

Adds OpenAPI specification of Storefront and Admin APIs.
Updates docs project.

docs-util/fixture-gen/src/services/test-pay.js

@@ -0,0 +1,59 @@
+import { PaymentService } from "medusa-interfaces";
+
+class TestPayService extends PaymentService {
+  static identifier = "test-pay";
+
+  constructor() {
+    super();
+  }
+
+  async getStatus(paymentData) {
+    return "authorized";
+  }
+
+  async retrieveSavedMethods(customer) {
+    return Promise.resolve([]);
+  }
+
+  async createPayment() {
+    return {};
+  }
+
+  async retrievePayment(data) {
+    return {};
+  }
+
+  async getPaymentData(sessionData) {
+    return {};
+  }
+
+  async authorizePayment(sessionData, context = {}) {
+    return {};
+  }
+
+  async updatePaymentData(sessionData, update) {
+    return {};
+  }
+
+  async updatePayment(sessionData, cart) {
+    return {};
+  }
+
+  async deletePayment(payment) {
+    return {};
+  }
+
+  async capturePayment(payment) {
+    return {};
+  }
+
+  async refundPayment(payment, amountToRefund) {
+    return {};
+  }
+
+  async cancelPayment(payment) {
+    return {};
+  }
+}
+
+export default TestPayService;