Control behaviour for LaneSplitter (since splitters got it)

[Sunrosa]

Regular splitters were given the ability to connect to the circuit network recently, but LaneSplitter entities are still unable to connect, even I assume they function almost exactly the same as splitters, so it would probably be pretty simple to implement (?), and it feels natural to add the ability to control it like splitters. I imagine it would greatly open up possibilities for compact lane-balanced balancer builds.

[eugenekay]

Previously