SaaS upgrade behaviour

[mesellings]

We should look at whether to add information into the SaaS documentation about what happens during a cluster update.

It might be a quick win to change the warnings in console, so upgrading a cluster sounds less scary. Maybe also a section in the docs about the SaaS upgrade behaviour would be nice...do we perform rolling updates for zeebe? currently there is just a generic warning when updating the cluster: "Camunda components will be temporarily unavailable"
It mentions that components will be unavailable because some of our web applications are doing data migrations during updates and this can lead to longer update time with downtime. For Zeebe this shouldnt be the case.

Change the warning:
e.g. something like:

• "Operate, Optimize, and Tasklist are temporarily unavailable during cluster update. Zeebe remains operational."
• "Zeebe remains operational during a cluster update, but Operate, Optimize, and Tasklist are temporarily unavailable until the update completes."