Convert Python license classifiers to SPDX expressions

[befeleme]

To make it work it was needed to:

• change the Trove - Fedora mappings (remove Callaway expressions, add SPDX)
• delegate the compliance check of Fedora licenses to a source maintained by the Fedora Legal team
• move betamax configuration to conftest.py to achieve a reliable global setting
• rewrite several tests that were blocked by licensing issues of the previously used packages
• regenerate all betamax cassettes

This is a best-effort solution which can't (nor aims to) cover the edge-cases. Unless Python adopts SPDX standard, this will always be approximation.

[befeleme]

Moved to draft, I also want to simplify is_good_for_fedora to escape the indentation hell.

[befeleme]

The finding from the latest review were incorporated and all squashed together.

[befeleme]

Overall looking good. Added a couple opinionated suggestions.

Thank you, I kept all of them.