[Windows] refactor stats package to fetch EBS Volume stats for Windows

[rawahars]

Summary

Presently, the code path in stats package of the agent, which invokes the CSI Client to fetch volume metrics, is limited to Linux platform only. The same code path can be used for Windows as well.

This change refactors the existing code to ensure that the EBS volume stats are collected for Windows as well in addition to Linux.

Implementation details

Refactor the code from Linux specific files to common platform files.

Testing

Using unit and integration tests for Windows and Linux.

New tests cover the changes: N/A

Description for the changelog

refactor stats package to fetch EBS Volume stats for Windows

Does this PR include breaking model changes? If so, Have you added transformation functions?

No

Licensing

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.