FIX installation and workflows

[gesinecauer]

The following changes were made to the installation:

• Moved all static content from setup.py to pyproject.toml (as suggested by PEP 517)
• Require cython (necessary for successful build of extensions)
• Fix typo in normalization extension
• Require setuptools>=77 (allows use of updated syntax for specifying license, per PEP 639)
• Require python>=3.9 (allows use of setuptools>=77)
• Added [project.urls] (documentation page, repository, etc)
• Added to classifiers and keywords sections

The following changes were made to the Github workflows:

• Prevent timeout (timeout-minutes: 10 and fail-fast: false)
• Update minimum python version to 3.9 (see above)

[gesinecauer]

Note that the version of ICED on PyPI (0.5.13) installs successfully on python 3.8, but not on any of the subsequent versions of python.

Hopefully requiring python >= 3.9 for the current version of ICED will be okay...

[NelleV]

Thanks!