Add placement group assignments to worker / worker groups

[steruck]

How to categorize this issue?
/area networking
/area high-availability
/kind enhancement
/platform aws

What would you like to be added:
Assignment of placement groups to worker / worker groups.

Why is this needed:
Placement groups can be used to control how instances are spread across underlying hardware in hyperscaler environments [1]. Depending on the type of workload, it is possible to define placement group to put instances close together or across distinct underlying hardware.

[1] Placement groups - https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html

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