Update documentation about os-image workload cluster update
What does this MR do and why?
Add documentation about os-image update during workload cluster update. Especially for CAPM3 case.
Later edit: there's a repo dedicated to doc and the work proposed here was integrated into sylva-projects.gitlab.io!64 (74d0d0a2)
Related reference(s)
Edited by Bogdan-Adrian Burciu