Idea: add ss3 .gitignore template to community/ directory on Github's gitignore repo

[ChristineStawitz-NOAA]

I was recently adding a bunch of stock synthesis-specific file extensions to a .gitignore for a project and realized your team must do this a lot too. Maybe it is worth a .gitignore template we could reuse?

I think usage is too low to put it in the general github dropdown but if you look at the README in this repo, they have a "Community" folder that seems like it could fit the bill.

https://github.com/github/gitignore

[k-doering-NOAA]

@ChristineStawitz-NOAA This is a great idea! Thanks for the suggestion, I'll look into it when I have the time :) (or feel free to make one, if you are feeling motivated!)