Utilizing a custom box for AWS, updating readme requirements, removing
all unrelated config/comments from Vagrantfile, documenting how to store
AWS config outside of SCM.
Fixed bootstrap to properly run r10k, and install git for VirtualBox.
Breaking out configuration more explicitly for VirtualBox, Fusion, and
AWS. Renaming boxes to try and somewhat standardize
(provider-os-version-arch-vmtype)
Updating readme, getting rid of any default box stuff in favor of
forcing the user to choose a provider, which avoids weird config
overlaps