Modernize build configuration to get rid of `setup.py`

[Neverhorst]

Description

Removed setup.py and moved all package metadata and requirements into pyproject.toml. Adjusted documentation and github release workflows accordingly. Release process now uses build as build frontend.

Also fixes the numpy package version to below 2.0 because some dependencies are apparently not yet compatible with the new major release.

Motivation and Context

Although using setup.py is still not deprecated officially, it is much more future-proof and less ambiguous to use pyproject.toml. For more information on the topic you can start here. This also allows to avoid setuptools as build frontend.

How Has This Been Tested?

• Local installation of qudi-core (editable and non-editable) in fresh Python 3.10 virtual environments.
• Performed build steps and Test PyPI publish locally

Types of changes

• [ ] Bug fix
• [ ] New feature
• [x] Breaking change (Causes existing functionality to not work as expected)

Checklist:

• [x] My code follows the code style of this project.
• [x] I have documented my changes in /docs/changelog.md.
• [x] My change requires additional/updated documentation.
• [x] I have updated the documentation accordingly.
• [ ] I have added/updated the config example for any module docstrings as necessary.
• [x] I have checked that the change does not contain obvious errors (syntax, indentation, mutable default values, etc.).
• [ ] I have tested my changes using 'Load all modules' on the default dummy configuration.
• [ ] All changed Jupyter notebooks have been stripped of their output cells.

[timoML]

@prithviulm, @astropiuu Can you merge the pyproject.toml of this PR with yours for testing? Just to make sure we're not introducing something here that is creating issues with a future PR for the testing framework.