Print elevator server's device ID.

Print elevator server's device ID.

This simplifies identifying the target elevator when there are multiple
of them running.

Also, remove hardcoded device ID in the configuration file so multiple
servers don't conflict.

Change-Id: I18b318c844e769529ae9f50e79ff85114a9f5b6d
Signed-off-by: Soemin Tjong <stjong@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/18489
Reviewed-by: Way Vadhanasin <wayvad@microsoft.com>
Reviewed-by: Ibrahim Esmat <iesmat@microsoft.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Alex Kelley <alexke@microsoft.com>
Reviewed-by: Dave Thaler <dthaler@microsoft.com>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>