Extend documentation on how to set up the virtual environment

[tobiasdiez]

In #30371 a minimal documentation on how to set up the virtual environment using pipenv is added.
This should be expanded to also include plain python -m venv and virtualenv (20.x).
Moreover, it would be good to describe the different ways to create an in-place installation.

CC: @mkoeppe

Component: documentation

Issue created by migration from https://trac.sagemath.org/ticket/31342