WIP: Feature/erp5testnode playbook test

Depends on https://lab.nexedi.com/nexedi/slapos.package/merge_requests/150

Might become a generalization of in-vm-test, depending on more knowledge provided during research/development.

in-vm-test could be a way to run a given script inside of the VM, which is able to provide output readable by erp5testsuite.