Consolidate sriov agent and driver code

Consolidate sriov agent and driver code

In preparation for decomposing the built-in reference implementation,
this commits consolidates the sriov agent and driver code into a
coherent place for it's life in the new repository. I've also given
the unit tests a new home.

DocImpact
UpgradeImpact

Partially-Implements: blueprint reference-implementation-split
Partial-Bug: #1468433
Closes-Bug: #1427317

Change-Id: Ic8b5215de76e191030228bc28773cd6535e889d8
Signed-off-by: Kyle Mestery <mestery@mestery.com>