Quantity/Units API

[andrewgsavage]

Following the discussion in #2101, I reached out unyt and astropy to collabrate on a Quantity/Units API to allow code to be written that supports pint and another unit libraries simultaniously. There has been some discussion here astropy/quantity-2.0#23 , showing there is sufficient interest in the idea, and it has now moved to its own group https://github.com/orgs/quantity-dev/discussions

If anyone is interested please make yourself known in this issue: astropy/quantity-2.0#23
@hgrecco , @jules-ch , @dopplershift @dalito