Legacy editable installs with pip are deprecated

[Brow71189]

Following the instructions for a developer installation from our wiki https://github.com/nion-software/nionswift/wiki/Developer-installation#installation-notes:

# editable install type checking: see https://github.com/python/mypy/issues/13392
# use the following line on macos before running the commands below
export SETUPTOOLS_ENABLE_FEATURES="legacy-editable"
# use the following line on windows
set SETUPTOOLS_ENABLE_FEATURES=legacy-editable

python -m pip install --no-deps --editable nionutils
python -m pip install --no-deps --editable niondata
python -m pip install --no-deps --editable nionui
python -m pip install --no-deps --editable nionswift
python -m pip install --no-deps --editable nionswift-io
python -m pip install --no-deps --editable nionswift-instrumentation-kit
python -m pip install --no-deps --editable nionswift-video-capture
python -m pip install --no-deps --editable nionswift-eels-analysis
python -m pip install --no-deps --editable nionswift-experimental

Leads to the following deprecation warning with latest pip (24.2):

DEPRECATION: Legacy editable install of nionutils==4.11.0 from file:///C:/Users/andreas.mittelberger/git/nionutils (setup.py develop) is deprecated. pip 25.0 will enforce this behaviour change. A possible replacement is to add a pyproject.toml or enable --use-pep517, and use setuptools >= 64. If the resulting installation is not behaving as expected, try using --config-settings editable_mode=compat. Please consult the setuptools documentation for more information. Discussion can be found at pypa/pip#11457

For now everything works fine, but I just wanted to bring this to our attention here so that we don't get surprised by this behaviour change in pip 25.0.