Feat(run_only): Add cloud storage support and remove PVC dependency

[huaxig]

This commit enhances the run_only.sh script by adding support for ephemeral storage (temporary volume in pod), allowing benchmark results to be saved to local directories or cloud storage buckets (GCS and S3), removing the previous requirement of a PersistentVolumeClaim (PVC).

Key changes:

• Flexible Output Destinations: The script now accepts a local filesystem path, a GCS bucket (gs://), or an S3 bucket (s3://) via the -o/--output flag, providing flexibility for result storage.
• Removed PVC Requirement: When an output destination is specified, the harness pod now uses an ephemeral emptyDir volume, eliminating the need for a pre-configured PVC. The PVC workflow remains the default if no output is specified.
• Unified Input/Result Handling: The logic for validating/processing inputs/results has been centralized. A _storage_type variable (pvc, local, or cloud) is used to streamline the workflow.
• Added upload_results function: The upload_results function is added to handle both copying results to a local directory and uploading them to a cloud bucket.

Examples

This update is back compatible, by default, it is still using PVC as target. To replace the result's destination, you can invoke the script by below examples. it will avoid PVC and pull results from pods directly.

• ./run_only.sh -c config.yaml -o ./results # Local folder
• ./run_only.sh -c config.yaml -o gs://mybucket/benchmark_results # GCS bucket