ReadGridded should support cropping geographically

[thorbjoernl]

Is your feature request related to a problem? Please describe.
Reading the entire griddeddata is quite memory intensive and discarding unneeded data (or ideally not reading it in in the first place) would be useful.

Describe the solution you would like to see

• Ideally, read calls would allow passing a bounding box and data outside of this bounding box is not read.

Additional context
Add any other context or screenshots about the feature request here.

[lewisblake]

Note: this will not work out of the box for non-lon-lat grids. So this PR will have to be limited in scope to only implement what xarray offers (e.g., .sel on longitude and latitude)

[lewisblake]

Another note: We want this to be implemented in such a way that it does not cause the data to be realized in memory earlier than the current implementation.

[heikoklein]

@thorbjoernl Please specify the setup you are using and where you think extensive memory is used (in the log-files).

E.g. for collocation, we are never reading the complete gridded data, just a few time-slices of gridded data, and are then only keeping the lat/lon variables. Memory usage and time usage are tune to work well here.

[thorbjoernl]

I originally created this issue because I ran into memory issues with some of the work I did with David (which we worked around by using the workers). This isn't critical for my purposes anymore, and if what you say is correct it may not even be that relevant to reducing memory usage. So I'd say this issue may be closed.

That being said, I know @lewisblake also wanted this functionality, so maybe ask him as well.