Drop support for Python <3.11 and NumPy <1.x

[tifuchs]

There are a few legacy syntax issues that can be replaced when dropping support for python <3.11:

PEP585
PEP604

Release 1.5 will be the first version to require python >=3.11.

[tifuchs]

I added ruff (pip install ruff pyupgrade) linting rules to the repo in bb89a41.

running ruff check . --fix should find and refactor easy syntax changes for newer python and numpy versions (for example the np.float -> float changes could have been solved automatically with this tool). It will also emit syntax 'errors'. Currently: still ~1000 remaining that cannot be changed easily.

Current python target version is 3.10 / numpy 2.x for release 1.5. (i.e. python <= 3.9 will be dropped)

[tifuchs]

NumPy 1.x is end-of-life:

orGUI version 1.4.1 will be the last version to support NumPy 1.x.

[tifuchs]

v1.5.0 still supported numpy 1 and python 3.10. (maybe even python 3.9, but this is untested)