The current implementation of --enable-editable uses pip install --editable --no-build-isolation (with SETUPTOOLS_ENABLE_FEATURES=legacy-editable in
build/pkgs/sagelib/spkg-install.in), which goes through legacy setup.py develop.

Here we change to the PEP 660 implementation in setuptools 65.x from #34344. We drop --no-build-isolation too, so that setuptools from the wheel, not the installed setuptools 63.x is used.

Depends on #32874

CC: @kwankyu @saraedum

Component: build

Branch/Commit: u/mkoeppe/use_pep_660_editable_wheels_for_sagelib @ 48576c8

Issue created by migration from https://trac.sagemath.org/ticket/34209