Although there aren't any Jenkins packages deployed that use a launch daemon, soon there will be.
Let's make the preinstall capable of handling that already now.
Files under /Applications are usually owned by root and wheel, unless admin user has dragged it there. Jenkins is not an install-by-dragging kind of app.
This is consistent with Apple's guidelines for
LaunchAgents vs. LaunchDaemons. Daemons start at
boot, and are not associated with a user. Agents
on the other hand are associated with a specific
user.