feat(firebase): add firebase integration

packages/backend/src/apps/firebase/common/get-current-user.js

@@ -0,0 +1,13 @@
+const getCurrentUser = async ($) => {
+  const { data: currentUser } = await $.http.get(
+    'https://people.googleapis.com/v1/people/me?personFields=names,emailAddresses',
+    {
+      additionalProperties: {
+        skipAddingAuthHeader: true,
+      },
+    }
+  );
+  return currentUser;
+};
+
+export default getCurrentUser;