docs: oas (#197)

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

docs-util/setup.js

@@ -0,0 +1,7 @@
+const fixtureWriter = require("./fixture-gen/utils/write-fixture").default;
+const { dropDatabase } = require("pg-god");
+
+afterAll(async () => {
+  await dropDatabase({ databaseName: "medusa-fixtures" });
+  await fixtureWriter.execute();
+});