Add manufactured SystemJump event, EventHandler for manu subsystem

With this patch a SystemJump event will be raised whenever a ship/
station jumps between systems.
Expand manu event rjr methods to register subsystem event handling

Now manu::subscribe & remove_callbacks handles subsystem events
tracking in addition to entity based events

We may want to pull some of this into the centralized Omega module
at some point allowing other subsystems to leverage the logic
UI: Subscribe/unsubscribe to system_jump events on scene changes