clean up the dev_env

This patch cleans up lots of old un-maintained cruft in the
dev_env.

1. removes unmaintained node definitions from the Vagrantfile
2. remove Rakefile and supporting code. I wound up moving all of
the code to other projects.
3. update README

Change-Id: I07a9ad8413aa717bfc2fca1c08508172c143e654