Fix sphinx doc tests

[cyouri-csgroup]

No description provided.

[ytanguy]

I have two remarks :

• The automatic tests (CI) run but the other ("pytest -m "features or validation") fail because the "out" directory does not exist : it is deleted at the end of test_features_prepare.py (last test). All the following tests fail. If we run the other tests one by one, they run succesfully
• You let some commented code in conftest.py : could you remove it instead of comment it ?

Thanks @cyouri-csgroup for the corrections.

[cyouri-csgroup]

I removed the comment and I fixed the error cause by test_features_prepare.py. I still have an error on test_valid_vegetationmask. Can you take a look at it please ?