Make ansible-galaxy available from within edi project setup

[lueschem]

A lot of functionality can be made available through ansible roles that are available all over the place.

ansible-galaxy (requirements.yaml) is probably the way to pull such additional roles.

Some functionality of edi-var/edi-pi/edi-cl can then be offloaded to such separate roles.

[lueschem]

Furthermore, the entire Ansible setup could be reduced to one single playbook pulling in a bunch of roles.