Container Storage Interface (CSI) support

[akutz]

Summary

The Container Storage Interface (CSI) is an open and collaborative effort with participants that include Docker, Kubernetes, Mesosphere, and the open source community as a whole. The goal of CSI is to define an industry standard implemented by storage vendors (SP) that enables container orchestrators (CO) to consume storage via a universal and well-known API.

This issue tracks the work required to enhance libStorage with a server-side endpoint that adheres to the CSI API specification as well as one or more CO-specific CSI clients.