Improve path mangement

[Char-Al]

Since python 3 it is recommended to use pathlib rather than os.

So It will be a good idea to migrate the code with pathlib.

Sources :

• https://towardsdatascience.com/dont-use-python-os-library-any-more-when-pathlib-can-do-141fefb6bdb5#:~:text=The%20OS%20library%20will%20return,be%20demonstrated%20in%20later%20sections.
• https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/