globally unique, persistent IDs

[mobb]

TDWG recommends a persistent, globally unique identifier
https://dwc.tdwg.org/terms/#occurrence
https://dwc.tdwg.org/terms/#event

An identifier for the set of information associated with an Event (something that occurs at a place and time). May be a global unique identifier or an identifier specific to the data set.

GBIF uses occurrenceID and eventID to replace records, so these need to be controlled.
See notes 2020-05-14

[clnsmth]

@mobb, how should we proceed with this one?