CAPO: use diskimage-builder image in CAPO CI jobs
We don't use images produced with diskimage-builder image in CAPO CI jobs yet (we use other images installed on the OpenStack instance used for those jobs).
Of course, we should do that!
Context: #505 (comment 1556502736)
This issue is dependnat on : sylva-projects/sylva-elements/diskimage-builder!44 (merged)
Edited by Marc Bailly