python-3.11.7: build a new 'package python'

Some more relevant version numbers (apps and libs):

  meson:           1.3.0
  snakemake:       7.32.4
  spyder:          5.5.0

  numpy:           1.25.2
  pandas:          2.1.4
  matplotlib:      3.8.2
  scipy:           1.11.4
  scikit-image:    0.22.0
  jupyterlab:      4.0.9
  torch:           2.1.2+cu118
  tensorflow:      2.14.1

Tensorflow 2.14.1 was build against /pkg/cuda-11.8.0-0.
It requires now bazel 6.1 (or higher), which in turn
is only happy with a more recent JRE, so java21 was choosen.

Tensorflow's CPU architecture is no longer 'nehalem', but
'broadwell'. Most of our cluster machines should be able to
handle this.

A more general change is the deprecation of source builds via:

  'python setup.py build; python setup.py install'

Now replaced with the recommended way:

  'pip install .', or
  'pip install git+https://github.com/xyz/abc.git@v1.0'

As for the QT5 bindings, here nothing was changed. For QT5
I expect no dramatic changes anymore. At some point QT6 will
join in or replace QT5.

Other changes and removals:

  'helen' does not build anymore, removed
  Older 'gmpy' was replaced with 'gmpy2'

Note on the strategy to avoid downgrades:

  If a package requires 'pkgXY' it installs the
  most recent versison. A follow up might want a slightly
  older version, so before 'pkgXY' is installed, just
  install this older requirement with oldie==1.2.3
  (see urllib3 as example)