This commit introduces a new parameter "OCTAVIA_NODE", which
is standalone by default. Only the main (for ha) or standalone
nodes create resources like accounts, the management network,
images, etc.
We also introduce a multinode vagrant configuration.
A follow up patch will introduce an haproxy in front of the octavia
API endpoints.
Change-Id: I835ee7e0e925232b55f3c14eeed98aeb0f0ce463