[Feat][operator] Support customizing autoscaler container command and args

[fangyinc]

Why are these changes needed?

Currently, the autoscaler container's startup command is hardcoded in BuildAutoscalerContainer function:

Args: []string{
    "ray kuberay-autoscaler --cluster-name $(RAY_CLUSTER_NAME) --cluster-namespace $(RAY_CLUSTER_NAMESPACE)",
},

Users cannot customize the autoscaler startup command for debugging purposes or to use a custom autoscaler image with a different entrypoint.

This PR adds Command and Args fields to AutoscalerOptions in the RayCluster CRD, allowing users to override the default autoscaler container command and args.

Usage Example

apiVersion: ray.io/v1
kind: RayCluster
metadata:
  name: raycluster-autoscaler
spec:
  rayVersion: '2.52.0'
  enableInTreeAutoscaling: true
  autoscalerOptions:
    command: ["/bin/bash", "-c"]
    args:
      - |
        echo "Starting custom autoscaler..."
        ray kuberay-autoscaler \
          --cluster-name $(RAY_CLUSTER_NAME) \
          --cluster-namespace $(RAY_CLUSTER_NAMESPACE)

Related issue number

Closes #4538

Checks

• I've made sure the tests are passing.
• Testing Strategy
  • Unit tests
  • Manual tests
  • This PR is not tested :(

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[fangyinc]

@Future-Outlier PTAL. Thanks you~