Add support for numpy 2.x

[teutoburg]

Also needs that in some of our internal dependencies (see sub-issues).

IIRC, there are a few cases like np.trapz in the codebase that need to be changed, shouldn't take long.

[teutoburg]

Added the Poetry 2.x task as a sub-issue because if we already have to modify our dependency specifications, it would be useful to already have them in the new (old) format beforehand.

This also sortof applies to all the sub-issues that are the same, but I won't create another set of subsub-issues for those...