Convert a Candump dir of log files to json

• Modify the makefile to use your local candump dir
• Run as many conversions as you have threads

  make -j `nproc`

Extract a specific message type from a candump.json

  cat candump-2024-10-05_094603.json | jq --compact-output '. | select(._meta_.dtype == "uavcan.si.unit.length.Scalar.1.0") | {ts: ._meta_.ts_system, id: ._meta_.subject_id, meter: .meter}'