filters in collapsible cascading menu

[k-doering-NOAA]

From Patrick:

This isn't a critical development need or anything, but I've generally thought that one of those collapsible cascading menus could be useful to have on the site. Basically something like:
Fish and fisheries >> Assessment Models, Forecasting, Stats, etc. >> then model names under each category
Ecosystem
PR
etc
These are just random thoughts on bins, something the FIT Committee would flesh out, but it seems like it could be a handy and familiar navigation tool. Anyway, just for consideration, and if I didn't explain it well I'm happy to chat.

I'm thinking of something like the "+" menu on the right in this site.