Adding ULID DataValue

[Quarmire]

Hi all,
I would like to use ULID as a DataValue in CozoDB since ULIDs are inherently lexicographically sortable. Hopefully, this will allow for as good as if not better data locality than UUIDv1. I've forked cozo and implemented ULID using the 'ulid' crate, and, so far, my initial test use seem to work. No benchmarks yet, but if someone shows me how I could quantify the gains of ULID indices, I could give it a shot.