Use the new cmake FindPython strategy

[dolfim-ibm]

According to this recommendation, we should soon switch to the new FindPython strategy.

Unfortunately, our initial tests showed that the FindPython strategy is mostly ignoring the hint Python_ROOT_DIR and defaults to the system python. This is then breaking all the python wheels which are generated.

This could be caused by the Python3_FIND_STRATEGY (default is VERSION) which might look for all python and then choose the most higher version. We should try with LOCATION, and see if it is able to be stick to the proposed Python_ROOT_DIR.

[dolfim-ibm]

Some isolated tests here: https://github.com/dolfim-ibm/cmake_pybind_ci/actions/runs/11139865676