[draft] add vcpkg support

[geiseri]

This is by far the smallest (read clean) cmake quickstart I have seen. At the risk of adding bloat I made a change so that vcpgk can be used instead of git submodules. To do that I did break use_submodules and changed it to externals with values of submodules, vcpkg, and none. I do not like the name for externals, but its a draft. My big concern is that I was unable to get some of the tests to pass on my system dispite manually touchtesting working. I will argue that untested code is implicitly broken code ;) I am not interested in wasting your time, so if you are not interested in this PR I can continue on my own, since it works for my specific needs. If you are interested and could offer a little guidence on why its failing that would be awesome. Thanks for you awesome cookie cutter!