Restructure launch files.

[andrewjong]

Pull the launch files out from inside the code. Right now it's too hard coded like that. We want it to be in the top level launch package so that people can compose and choose different launch files.

[andrewjong]

Then we should also make MACVO trigger based on launch file arg, NOT environment arg

[andrewjong]

Launches for sim-only, hitl, and real world.
Probably different param files for each of these.
Maybe have a common/ folder as well.
Try to reuse code as much as possible.