chore: add function to return storage amount and abbreviated units

[vinayak-kukreja]

We currently do not have a way to return the unit in a way that would work in Kubernetes. This PR would be a prerequisite PR for this issue: https://github.com/cdk8s-team/cdk8s/issues/1166.

We are converting memory units to mebibytes and ephemeral-storage to gibibyte even if user passes something else. This does not seem correct. For instance, here. So this PR would help resolving this issue. I believe this issue is another instance of being impacted by us converting the inputs.