Refactor all path handling to use pathlib

[daniel-j-h]

Python3's pathlib abstracts path handling and provides functionality which is otherwise not present or scattered across several modules. In addition it overloads operators for easier path joining.

from pathlib import Path

https://docs.python.org/3/library/pathlib.html

We should refactor all path handling in all our tools to use pathlib.

Tasks:

• [ ] Use pathlib for everything path related