Manage the new Gizeh data in xdem-data

[marinebcht]

Update examples.py to use this data from GlacioHack/xdem-data#4

[rhugonnet]

@marinebcht I already need to add some data in xdem-data for the point cloud PR in the next days.
If the data is publicly available in CARS/other, send me the link and I can do both at once 😉

[marinebcht]

Hi, this is where I took the input data https://cars.readthedocs.io/en/latest/quick_start.html
Easy to run CARS with the docs :)