devspace should run on a shared docker host

[manics]

Currently devspace is designed to work on a dedicated VM. Due to the overhead in managing VMs it would be a lot easier if multiple devspaces could run on a shared docker host.

[sbesson]

@manics is this partly or fully addressed by #74?

[manics]

it might be. I haven't tested whether all the jobs are working (due to the need to setup ssh keys, etc).

[jburel]

As mentioned during the training prep, we will still need to use openstack for the time being for most of the team