Transition to Apache License 2.0

[vschaffn]

Description

This PR implements the transition to Apache License 2.0.
Resolves #646.

Changes implemented

• The LICENSE file has been updated with the full text of the Apache v2.0 license.
• A NOTICE file has been added to comply with Apache licensing requirements. The file includes necessary copyright notices and details about dependencies used by GeoUtils.
• An AUTHORS.md file has been created listing the main contributors of the project along with their contact information, while mentioning their affiliation with the GeoUtils developers' copyright.
• All source code files have been updated with the Apache v2.0 license header which is in .github/scripts.
• The setup.cfg has been updated with the new license and copyright as well as conf.py.
• The documentation has been updated with the license and the authors.
• Some packages have been added to the virtual envionment config files to match with the notice.

Notes

• I kept the same "Develoment Lead" and "Original developers" parts as xDEM in authors.md, do not hesitate to say if these informations are true as well for GeoUtils or not.

[rhugonnet]

It all looks great, thanks a lot @vschaffn! 😄

Regarding your note: Indeed, for GeoUtils, @atedstone should also be listed as creator/lead. 😉

I saw @adehecq posted an a posteriori comment about sharing our emails here: GlacioHack/xdem#617 (comment)
I also wonder if those emails are "protected" from being automatically read from spammers. This is the case when sharing your email through the GitHub profile, I think. But it's also more steps for interested parties/users to find them, and less inviting.
I haven't had any issues with it, so I don't mind leaving mine for now (my spam filter is already working a lot anyway...).

[vschaffn]

@rhugonnet thanks for your feedback. I added @atedstone to the list of creators/lead.
I removed @adehecq e-mail but I left yours 😃

[adebardo]

All good for me, just waiting for @adehecq review for his email choice

[adebardo]

We talked about the 10/02/2024 in a meeting, everything is okay

[adebardo]

ok