Create domain for rcal staging and point it to the backend and frontend

[prakashchoudhary07]

Issue: Currently backend is hosted on Render's Domain and frontend is on Vercel domain, so while authentication cookies are being set on Render's domain so they are not accessible in the frontend (Vercel domain), due to security reasons browser doesn't allow it.

Solutions:

1. Create sub-domains with the same domains second-level and top-level domains, so that cookies can be accessed
2. Host both frontend and backend on the same domain