NEP-29 - enforce minimum Python version 3.10

[pavoljuhas]

• Raise exception if running with Python <= 3.9.x
• Clean up checks and notes relevant for old Pythons
• Bump up to numpy~=1.22 which is effectively the minimum version that works with Python 3.10. We are a bit more permissive than NEP 29 which suggests numpy-1.23+.

Fixes: #6463 Ref: https://numpy.org/neps/nep-0029-deprecation_policy.html

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 97.79%. Comparing base (bfba965) to head (1aa3173). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #6591 +/- ## ========================================== - Coverage 97.79% 97.79% -0.01% ========================================== Files 1124 1124 Lines 95705 95704 -1 ========================================== - Hits 93595 93594 -1 Misses 2110 2110 ```

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