Add the base DevStack job and make sure bashate runs on
the devstack plugin files.
Begin to re-structure the plugin to match the common structure.
Add devstack/build.sh and split out the build steps into
separate functions in devstack/lib/stx-metal
This is complete, further work to be done in follow-up changes.
Change-Id: I05f6df758e18f182fb0a05731eddc6cb7f599e51
Signed-off-by: Dean Troyer <dtroyer@gmail.com>