User Story

As a user/operator I would like to use MHC for checking machine conditions

Detailed Description

As of today MHC allows user to configure health checks on node conditions only.
It would be great to have MHC to support also definition of health checks on machine conditions, thus allowing e.g. to check on conditions about etcd/control plane components added by KCP.

Anything else you would like to add:
Most probably this requires changes to

And

/kind feature
/kind api-change