core: host-deploy: Using ssh username and password to install and update host

Currently we provide installation only with root user. This patch adds
username and password fields to add and update vds command and makes
those parameters configurable for authentication.

Change-Id: I3d9b23771314ebebb3e10686decb4f0d5ace6d3c
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>