Enhance the workspace integration tests TestUploadDownloadBlob and TestUploadDownloadBlobViaServer

[jenting]

Bug description

Enhance the workspace integration tests TestUploadDownloadBlob and TestUploadDownloadBlobViaServer to make it available to run in locally, without necessary to build a container image and run a Pod within the Kubernetes cluster. If we run these two locally, it'd failed at DNS lookup the MinIO server minio.default.svc.cluster.local:9000 since there is no MinIO server locally. We should be able to port-forward MinIO port 9000 locally and change the integration test to DNS lookup the localhost:9000.__

Steps to reproduce

1. Create preview environment and kubectx to preview environment
2. Run the integration test

cd test
go test -v ./... \
  -run TestUploadDownloadBlob \
  -kubeconfig /home/gitpod/.config/kube \
  -namespace default
go test -v ./... \
  -run TestUploadDownloadBlobViaServer \
  -kubeconfig /home/gitpod/.config/kube \
  -namespace default

Workspace affected

No response

Expected behavior

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Example repository

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Anything else?

No response