Change installation instructions

[JoaoFelipe]

Considering we are dropping support for Python 2 in noWorkflow 2, we should probably remove the setup.py install command from the readme and use pip install -e . instead (or python -m pip install -e .), since Python 3 already includes pip and the installation is more reliable.

[Felipe-CdS]

Can I change this ticket idea to something like a Dockerfile? In my opinion using docker is way easier than managing python versions and libs. If a non-docker solution is preferred, maybe change the instructions to something like uv sync instead?