feat: STACCube authentication via GDAL bearer token

[mattyfromtheblock]

Description

This PR implements token based authentication for the STACCube via GDAL env (passed through stackstac and rasterio)

Relates to # (issue)
n/a

Type of change

Select one or more relevant options:

• Bug fix (change which fixes a bug reported in a specific issue)
• New feature (change which adds a feature requested in a specific issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update (improved documentation for existing functionality in the package)
• Repository update (change related to non-package files or structures in the GitHub repository)

Checklist:

• I have read and understood the contributor guidelines of this project
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I ran all demo notebooks locally and there where no errors

[mattyfromtheblock]

NOTE: One change in this PR is also covered by #60

The change in question concerns the deprecated "np.NaN" alias, which has been changed to "np.nan" (semantique already exclusively uses "np.nan" from what I've seen. So, the change should not cause any issues)

semantique/semantique/datacube.py

Line 940 in 7f62d9f

empty_arr = xr.full_like(extent, np.NaN)