Point to gopsutil fork with shirou/gopsutil#889 changes. I used hashicorp/gopsutil rather than pointing to https://github.com/Lomanic/gopsutil/tree/issue832 directly just in case..

This PR switches the Nomad repository from using govendor to Go modules
for managing dependencies. Aspects of the Nomad workflow remain pretty
much the same. The usual Makefile targets should continue to work as
they always did. The API submodule simply defers to the parent Nomad
version on the repository, keeping the semantics of API versioning that
currently exists.

The presence of Storybook’s preview-head.html file in the repository
is a constant annoyance: it’s only needed for Storybook and it changes
all the time, producing a lot of Git noise. By making it a separate
step to have the Ember CLI server running before starting Storybook,
we no longer need to have preview-head in the repository. It needed to
be present because there was a race condition where it was sometimes
not generated in time for the Storybook parallel startup.

Primarily don't ignore tags and bin packages in vendored folders

Allow users to customize their makefiles by adding custom
targets/variables without checking them in.

Also persist and load DeploymentStatus to avoid rechecking health after
client restarts.

Committing generated code to help ensure reproducible builds.

docker/pkg packages.