This is a rework of the repository packaging to:
* Renames project to akanda-horizon
* Moves all code to akanda_horizon module
* Updates setup.cfg/setup.py for PBR
* Moves openstack extensions to a subdir
This updates setup.cfg/.py for pbr, renames the project to akanda-horizon
and moves dashboard extensions into a subdirectory.
Change-Id: I5cb1dad2e7dd7f47d0bac2ac39bdf34348fa6240