Add the FE as a Submodule to the BE app and Serve FE bundle

[jagzviruz]

Add the FE repo as a submodule to the BE repo.
Following this make changes so that the BE app can serve the FE bundle as static assets, while continuing to serve as a API backend.

Approach open for discussions with @crysfel @charlesjliu

[crysfel]

I was thinking that we might want to keep hosting the frontend in github, mainly because is free, easy and super quick! Then we can have the backend in azure serving the frontend and also the alpha site (for now)