Install the Go toolchain on the admin node, and put it to use.

This switches from using apache for serving static content to using a
very basic webserver written in Go, and switches from chef-server to
goiardi, refactoring the bootstrap recipes a bit.
Build openwsman from source as part of bootstrap
Switch to using grub2 for PXE and UEFI netbooting
Split out most parts of the default crowbar-bootstrap recipe
A massive bootstrap refactor deserves a new docker admin image.