add a output for entity.connections for chain and rail signals

[hansjoachim]

Getting support for it would be really helpful for my mod as with it I can automatically place safe outputs for train intersections and automatically test all the intersections.

If I do

if entity.type == "rail-signal" then
connections = connections.entity

I get nil as connections.entity isnt support for rail signals.

In the debug it says that connections can be == back in, back out, front in or front out