More pint + cf-xarray usage in examples (#325)

* few minor updates

* use pint + cf-xarray

* Workaround for chunking bug in the cookbook

* minor fixes + add link to another example

* fixes and clarifications after review

* fixes and clarifications after review

* cf-compliant names/units

* Update for 'grid_latitude'/'grid_longitude'

---------

Co-authored-by: anton-climate <anton.steketee@anu.edu.au>