Cinder devref doc cleanups

Way back when Cinder was inagurated as a separate project, the docs
directory from Nova was used as a seed for the one in the Cinder repo

This patch is simply cleaning out images and files which have no
relation to Cinder at all, and are at best extremely outdated when
applied to Nova.

Aside from the deletions which are mainly images, and files related
to the configuration of CloudPipe, there is one modification to
conf.py which simply removes a reference to a vmware doc that no
longer exists.

Change-Id: I2140035f98bd332f25d7dd7569993bcd960a869e