Expose area of use

[jdries]

PyProj has this area_of_use CRS property:
https://pyproj4.github.io/pyproj/stable/api/crs/crs.html#pyproj.crs.CRS.area_of_use

It allows to check if a certain extent it within the valid bounds of the CRS, so exceptions can be avoided.
This is quite relevant when dealing with rasters that are larger then the valid area of a CRS. We for instance could use it here:
locationtech/geotrellis#3542

[pomadchin]

👍 Nice! If you're interested in implementing it I do my best to help you and to get it merged and released.