docs: oas (#197)

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

docs-util/jest.config.js

@@ -0,0 +1,22 @@
+const glob = require(`glob`);
+
+const pkgs = glob
+  .sync(`${__dirname}/*/`)
+  .map((p) => p.replace(__dirname, `<rootDir>/docs-util`));
+
+module.exports = {
+  testEnvironment: `node`,
+  rootDir: `../`,
+  roots: pkgs,
+  testPathIgnorePatterns: [
+    `/examples/`,
+    `/www/`,
+    `/dist/`,
+    `/node_modules/`,
+    `__tests__/fixtures`,
+    `__testfixtures__`,
+    `.cache`,
+  ],
+  transform: { "^.+\\.[jt]s$": `<rootDir>/jest-transformer.js` },
+  setupFilesAfterEnv: ["<rootDir>/docs-util/setup.js"],
+};