setup.py deprecation

For ALE development, when running `python setup.py install`, as directed in the readme, it displays this warning:

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Please avoid running ``setup.py`` directly.
Instead, use pypa/build, pypa/installer or other
standards-based tools.

This deprecation is overdue, please update your project and remove deprecated
calls to avoid build errors in the future.

See https://blog.ganssle.io/articles/2021/10/setup-py-deprecated.html for details.
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It looks like we should find an alternative.

Start with the installation instructions in the README and inspect setup.py to identify the deprecated installation path. Replace the documented and project-supported installation approach with a standards-based alternative, then verify that ALE can still be installed without the deprecation warning.

Written by the indexing model from the issue text.