Adjust transporter capacity and count based on path length in a room

[Mirroar]

The amount of transporters spawned in a room might not be sufficient when there are long paths between storage and sources / controller. This is especially true if links aren't built yet, or power creeps cause extra energy needing to be transported.

Either the room keeps track of transporter usage and adjusts numbers based on a rolling average, or we calculate a better estimate from the aforementioned factors.