Massively refactor how the raid barclamp works.

Do not merge yet -- I want feedback and discussion around how raid should work going forward.

This moves the raid control libraries from chef to being their own hammer.
This will allow other roles to create and destroy RAID volumes on the fly.

Right now, only discovery of megacli-controlled RAID controllers is
performed automatically, although volume creation and deleting work
normally when driving the raid hammer via the rails console.

The next step involves lots of wrangling about how we should handle
creating needed raid volumes for OS installation and workloads.  This
pull request still has a raid-configure role, although it is fairly
vestigal at this point and should probably be eliminated in favor of
roles that care about what kind of volumes they want driving things more
directly.