Replace LoKi distance calculator?

As can be seen in this flame graph

https://lhcbpr-hlt.web.cern.ch/PerfTests/UpgradeThroughput/Throughput_lhcb-master-mr.10989_Moore_spruce_all_lines_x86_64_v3-el9-gcc13+detdesc-opt+g_2024-03-12_02:26:08_+0100/

the sprucing spends a lot of time (25%?) in LoKi::DistanceCalculator. It should be possible to get this down by using simpler functions that do not rely on particle extraoplators (such as in the Thor functors).