ADR Suggestion: Standardize on Python version support strategies

[rozyczko]

We should have a way to determine when to stop supporting older python versions and when to start supporting new versions.

This is to a large extent dependent on our main dependency - scipp.

We could possibly mirror scipp's support management for Python versions and important packages like numpy, scipy etc.

However, there is a non-trivial issue with modules like PySide (and to a lesser degree - pyinstaller), which are very cranky wrt. version dependencies.

[rozyczko]

We need to also consider requirements for the calculators we use in our projects

• cryspy
• pycrysfml