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: Id39914e1286870373ad6f69360fa7b3ddfabd8df
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>