Put workflow guideliness on first entry page

This is the entry page for this effort:

https://salsa.debian.org/newgateway-team

I believe it should explain how to submit a package for review. We have that text here:

https://salsa.debian.org/newgateway-team/reviews

It didn't feel natural to go into that sub-directory to submit something. If the top-level README explained the process, or at least provide a link to the reviews/ sub-directory, that's better.

What do you think?