Support for generating .gitignore file using gitignore.io

[emerali]

It's a website that has a lot of useful pre-made gitignore files and also allows you to easily combine them (for example, i usually generate a gitignore combining the julia, visualstudiocode, and jupyternotebook ones)

Their api is pretty straightforward, and can be accessed using curl: https://docs.gitignore.io/install/command-line#linux-bash

[christopher-dG]

Not a bad idea, but I wouldn't want to add an HTTP dependency just for it. Maybe if I ever get around to adding the other web-related stuff...