This allows to reuse the same configuration declaration (especially vagrant which uses
the "staging" environment).
And not having to declare one especially for the vagrant nodes.
Note: I considered renamed the location from "vagrant" to "local" as local sounds more like a location
than "vagrant" (which is more an implementation detail on how we implement local vms). But I did not
act on this, if we agree on that, i'll do it in other diffs (that impacts the Vagrantfile as well).
Related to D3989#inline-27284 discussion