Deal consistently with Raster.data.mask=False

[rhugonnet]

The mask of a masked array can be just False and not an array of False when there is no nodata. This can lead to some problems in functions.
The function geoutils.raster.array.get_mask circumvents that issue by using np.isfinite(array) on the array if the mask is not an array, but that requires the array (which we wouldn't have necessarily loaded, see #502) and mostly more CPU usage.

We should have a consistent way to deal with this, maybe something similar to what is done in raster_equal here:

geoutils/geoutils/raster/raster.py

Line 988 in d0cd168

# If the mask is just "False", it is equivalent to being equal to an array of False

Or a "good practice" from the NumPy documentation?

[rhugonnet]

Good practice seems to be calling np.ma.getmaskarray(): https://numpy.org/doc/stable/reference/maskedarray.generic.html#accessing-the-mask