Remove dependency on "entrypoints" feature of setuptools
The modulegraph script is implemented using the "entrypoints" feature of setuptools. I'd prefer to get rid of this dependency to make it easier to switch to "packaging/distutils2" in the future.
Just drop the script and switch to "python -m modulegraph" to get the same functionality.
Switch to a classic distutils hook for specifying scripts (and write said script)