Once we are able to use GitHub tokens, prompt users to create one in create_existing_recipe_list()

[homebysix]

Once #18 is built out, we should prompt users to create a GitHub token if they don't already have one. I don't think we should actually handle creation of the tokens, but at least a [WARNING] that tells them it's a good idea would be nice.

[sheagcraig]

If we lift this straight out of AutoPkg, wouldn't we also be getting the creation stuff?

[homebysix]

Sure, if it's already built. I've never used AutoPkg to create a token.

[eahrold]

It's super easy, and the AutoPkg code is a good place to start, but it needs some attention since it's scope is pretty narrow.

I've done some personal reworking on that code, and recipe-robot may be a good place to roll it out a reworked version and some day offer it back up AutoPkg.

[homebysix]

Long shot, but do you still have that reworked token code handy?

If not, no worries. But I'm probably going to start on this and didn't want to reinvent your very round wheel.