Allow installation without installing service

[jehontan]

Describe the feature

When installing using the .deb, a service is automatically installed and systemctl invoked. This causes problems when installing in a container where systemctl is not available.

Installing from source is workaround, but adds unneeded complexity.

Installing the service should be an optional feature, as most ROS users will likely invoke the executable directly, through a script or through rosrun/roslaunch, and the service is probably only used by a minority of users.