Handling a ROI when loading dem, add stats documentation

[vschaffn]

Resolves #602.
Completes GlacioHack/geoutils#642.
Completes GlacioHack/geoutils#638.

Description

This PR introduces the ability to use a Region of Interest (ROI) when working with xdem.DEM, which is a subclass of geoutils.Raster. This functionality allows users to focus on specific regions within the raster data without having to load or process the entire dataset.

Documentation

• A section about statistics has been added to the DEM class documentation.
• A section about the ROI has been added to the DEM class documentation.

Example

1. Statistics:

• Get all statistics in a dict:

dem.get_stats()

• Get a single statistic (e.g., 'mean') as a float:

dem.get_stats("mean")

• Get multiple statistics in a dict:

dem.get_stats(["mean", "max", "rmse"])

• Using a custom callable statistic:

def custom_stat(data):
    return np.nansum(data > 100)  # Count the number of pixels above 100
dem.get_stats(custom_stat)

Note: as get_stats() is a raster method, it can also be used for terrain attributes:

dem.slope().get_stats()

Note

• This PR has to be merged after the next release of geoutils containing Handling a ROI when loading raster data geoutils#642, Adding statistics to Raster geoutils#638.
• The geoutils version in the virtual environment configuration files (environment.yml, dev-environment.yml, ...) would have to be updated.

[vschaffn]

Tests with the correct geoutils version with ROI:

[rhugonnet]

All good for me! I don't have any other comments than the ones that are in the GeoUtils' PR.