This commit adds the ability to build a standalone provisioning tool. This is the first useful public mcl code base as well. It is not perfect, but does serve as a rough starting point to show what is possible. In the future as the language and the engine evolve, this will likely get more elegant, and also grow new features. To build this, run `make clean && GOTAGS='embedded_provisioner' make`. To run this, run `mgmt provisioner`.