Add support for DEPLOY_SSH_BATCH_MODE with default of yes.

Add support for DEPLOY_SSH_BATCH_MODE with default of yes.
Before this update all remote commands were bunched together and
sent to the remote host in a single SSH command.  This could result
in a very long sequence of commands that might be rejected by a
remote host (example is VMware ESXi that uses busybox sh).
With this update you can set DEPLOY_SSH_BATCH_MODE="no" and
each remote command is sent as a separate SSH call so now we
do not have big long sequence of commands.  Defaults to same
behaviour as before this update.