Adds diskimage-create scripts to pypi package
Adds diskimage-create scripts to pypi package

This patch adds the diskimage-create script and associated files
to the pypi package under share/octavia so that operators have the
required script to be able to build amphora images.
This also includes the README and LICENSE file for octavia.

Change-Id: Id014c4ac067de223f15a6bc2382aa2529cf89a13
Closes-Bug: #1654099

openstack/octavia,openstack/octavia,openstack/octavia