User Story:

As a (user persona), I want to be able to:

• Choose what expander is used by the cluster-autoscaler

so that I can achieve

• customize how my node groups are scaled.

Acceptance Criteria:

Description of criteria:
Add support through the HostedCluster API `.spec.ClusterAutoscaling` to choose a set of expanders for the cluster-autoscaler.

See available expanders: https://github.com/kubernetes/autoscaler/blob/master/cluster-autoscaler/FAQ.md#what-are-expanders

(optional) Out of Scope:

Detail about what is specifically not being delivered in the story

Engineering Details:

• (optional) https://github/com/link.to.enhancement/
• (optional) https://issues.redhat.com/link.to.spike
• Engineering detail 1
• Engineering detail 2

This requires/does not require a design proposal.
This requires/does not require a feature gate.