Add ability to filter GCS (CRS) by unit

[ben-polinsky]

Add unit to CRS returned by getAvailableCoordinateReferenceSystems and allow filtering based on a case-insensitive unit string passed as an argument to the same function.

Also expose a function getAvailableCRSUnits which returns an array of all CRS units used. This is helpful because some units contain language variations: "metre" vs "meter", for instance, and it is useful to see what are known values.

Closes #8614

imodel-native: iTwin/imodel-native#1244

[aruniverse]

@simnorm @ashar-bentley @arome , plz review the api meets your expectations / needs

[hl662]

out of curiosity, is there any value in mapping the units returned here with names of ECUnits?

[ben-polinsky]

out of curiosity, is there any value in mapping the units returned here with names of ECUnits?

There could be. I think it is out of scope for this initial task.

[arome]

This looks great, in our use case we want to filter out one option. Do you think this should be implemented on the API level or should we just fetch everything and filter it out based on the unit you now added

[ben-polinsky]

This looks great, in our use case we want to filter out one option. Do you think this should be implemented on the API level or should we just fetch everything and filter it out based on the unit you now added

I think filter based on the unit.

[arome]

hey @ben-polinsky any update on this PR?