Ignore node_modules in repos
Reorganize aliases for git commands

There was too much duplication between the aliases and gitconfig files. Now,
we're going to favor defining "long" aliases in gitconfig and shorter
(2-lettered) ones in aliases.

Also, we're going to keep using hub for GH features - maybe gh later.
Let's use gitsh!

Also reorganize some of the Homebrew packages in laptop.local.