Add docker-cli capability

[clintoncwolfe]

Add the ability to connect to a docker container and run the hab cli within it.

[kekaichinose]

@clintoncwolfe with the blocker and epic closed, is this issue still valid?

[clintoncwolfe]

I'd say yes, this issues is valid; the epic was to get an MVP implementation (done) and the blocker was a blocker, meaning a thing that must be completed before this could be started, not closed.

That doesn't mean that we ever need to commit to this work. It's a feature request.