Add aggregate/rollup command for audit logs

[ezekg]

E.g. the extend action may be logged thousands of times per-node per-day, so being able to (optionally?) rollup that data would save a lot of disk space. But aggregation would come at the cost of auditability. Estimating ~95% savings here.

[ezekg]

See: https://bit.kevinslin.com/p/lossless-log-aggregation

[ezekg]

Should this be opt-in e.g. via --agg-audit-logs or --aggregate-audit-logs?

[ezekg]

Is this even needed now that we've tackled #19 and #20? Need to recalculate estimated savings.

Still need to optimize entity IDs in #22. Could likely use integer IDs + #25.

[ezekg]

No longer needed with 423bcc4. Estimated space savings of 65.79% with int columns.