The pathfinding engine built into the code has several configurable
parameters to adjust the depth of the paths indexed and explored.
These parameters can dramatically impact the performance and memory
consumption of a server; higher values can result in resource usage
increasing exponentially.
These default values were decided early and somewhat arbitrarily at
a time when the network and the size of the network state were much
smaller.
This commit adjusts the default values to reduce the depth of paths
to more reasonable levels; unless explicitly overriden, the changes
mean that pathfinding operations will return fewer, shallower paths
than previous versions of the software.