Clean up install script a bit
Clean up install script a bit

I moved some stuff around (package mkdir to a loop, clones to a code
block) so the whole script looks easier to digest.

It's a minor thing; I've mostly been working on some helper scripts for
cloning plugins into packages, so after I'm satisfied with it, I'll be
moving away from this script anyway so... ¯\_(ツ)_/¯

igemnace/my-vim-config,igemnace/vim-config,igemnace/vim-config,igemnace/vim-config