Add "well known annotations" list to UCUM validation support

[brynrhodes]

With UCUM validation support, any UCUM unit containing a valid annotation is allowed. But there are contexts that require supporting only a specified list of UCUM annotations. The UCUM validation should support this.

[brynrhodes]

Current known list:

'{copies}/mL'
'{beats}/min'
'{drinks}/d'

Other potential sources are the LOINC list of commonly used UCUM units: https://loinc.org/usage/units/.

The mechanism needs to support dynamic management of the list of available annotated units.

Note: Changed '{drinks}/day' to '{drinks/d}' (correct UCUM unit for days)