Make distances storage optional

[danpat]

With #5251, we finally caved in the name of performance, and we pre-calculate edge distance and store it. This makes requesting distance values from large table requests very fast.

However, not everyone needs this, and as we're C++ people, we don't believe you should pay for what you don't use.

#5218 captures the idea of making some data optional.

This ticket is specifically about the .distance property added by #5251. It should be possible to optionally generate it, and optionally load it, reducing the disk/memory overhead if you're not interested in this property.

[github-actions]

This issue seems to be stale. It will be closed in 30 days if no further activity occurs.