feat(portal): create a welcome page

[HasithDeAlwis]

🆘 What is the problem at hand?

Users need to be greeted with a welcome landing page when they go to our portal.

🚀 What is the impact of the problem? How is this problem important? How does it affect users/developpers?

It gives us a sense of professionalism and gives people a chance to learn about cuHacking without being prompted to login right away.