Consolidated devstack script

Based on https://review.openstack.org/#/c/110988/

One script to run tests on devstack for both murano components:
* murano-engine
* murano-dashboard
* python-muranoclient

Nodepool preparation script included.

Use separate tests for murano-dashboard because of a bug in horizon
    https://bugs.launchpad.net/horizon/+bug/1351298

Change-Id: I4f424cca68f0dcce8a1052f61703f4dc9891cb97
Merge "Consolidated devstack script"