Decide approval process

[STSpencer]

Somewhat related to #9 , we should agree an approval process about how packages that meet the criteria we defined are added to the list, and then also add text to the list telling users how to submit their packages to the list. To me, in the long run, it makes to do 1 Pull request/package add, then we can set up discussions on that PR if need be to refine the package listing up to whatever standards we decide.

Any thoughts?