Adds factory methods to load Hyper-V utils classes

Blueprint: hyper-v-wmi-v2

This patchset provides further decoupling between the ops modules
(e.g. vmops, volumeops) and the utils modules which handle the
interaction with the underlying OS.

The main reason for this refactoring is the need to provide an
implementation of the Hyper-V WMI V2 API (root\virtualization\v2)
that replace the initial version introduced with Hyper-V Server
2008.

Change-Id: I8a2dd8f7dea2e4044525866a0ab26211eb17bf99
Merge "Adds factory methods to load Hyper-V utils classes"