expand/refine README for nwfsc-assess organization

[iantaylor-NOAA]

Following guidance from github, I just created a new repo README for the nwfsc-assess organization that is outside the individual repositories. See the first draft here: https://github.com/nwfsc-assess.
The file is hosted in the new .github organization https://github.com/nwfsc-assess/.github/blob/master/profile/README.md

Please comment here if you have suggestions for changes to this file or think it's a bad idea to have it in the first place.
Better yet, just modify the file as you wish.

[kellijohnson-NOAA]

Thanks @iantaylor-NOAA for taking the time to do this. I think it is a great idea. I pushed one small change to the first sentence in b96b850.