Support label-based update flow in any strategy

[defo89]

How to categorize this issue?

/area ops-productivity
/area control-plane
/kind enhancement
/priority 3

What would you like to be added:

As an operator managing clusters with critical payload we would like to have an option to "control" machine rolling update process.

Label-based approval flow described in Manual In-Place Updates should be supported in AutoRollingUpdate any strategy.

Why is this needed:

• MCM labels nodes that need to be replaced with node.machine.sapcloud.io/candidate-for-update label
• An external actor can perform evaluation and approve selected node(s) with node.machine.sapcloud.io/selected-for-update

[defo89]

cc @hardikdr

[defo89]

I should’ve used “any upgrade strategy” rather than restricting it to AutoRollingUpdate, because AutoInPlaceUpdate should reasonably support this too.