Create engine kubernetes stack

This change creates kubernetes stack for engine in order to package,
deploy, and test stacks independently from engine core.

The main feature this enables is the ability to develop stacks
in their own repository with proper versioning and branching no
matter how the tools (provisioner and installer) are developed.
The stack simply selects versions of the tools (could be branches)
and the rest is done accordingly.

The role package which was previously located under
infra/installer/kubespray is moved into this repository in order to
handle what to package within the stack since some of the artifacts
we package do not belong to installer but to the stack itself.

Change-Id: I760d4d904544dad768525e999ebe53e156464111