Numpy 2.0.0 update and removing deprecated scipy modules

[hechth]

This PR is an initial attempt at porting the project to numpy 2.0.0 - so far running the tests manually after installing all dependencies seemed fine. I removed the deprecated scipy sparse functions and replaced them with the normal operator versions.

[hechth]

@mpenkov @gojomo @piskvorky could you run the CI on this and see if this works fine?

[piskvorky]

Done :)

[hechth]

@piskvorky argh the linter :D

[hechth]

@piskvorky could you re-trigger? Or is there a way how I can execute test in a way that is comparable to the CI?

[yoannspace]

@hechth @YoungMind1 Thanks for looking into this!
Can I also suggest to have a look at scipy >=1.14 (https://github.com/piskvorky/gensim/pull/3563/files#diff-60f61ab7a8d1910d86d9fda2261620314edcae5894d5aaa236b821c7256badd7R336)?
Since you already removed the scipy spartools in this PR (and if lucky there is nothing else to change)...

Edit: Sorry... Realized scipy 1.14 requires python 3.10 too late. Forget it, maybe in a later version.

[julianpollmann]

Upgrading numpy will fail tests, since saving in word2vec format will save keyvectors as strings of numpy datatypes instead of strings of floats.

[julianpollmann]

@hechth I opened a PR in your fork for fixing tests for numpy 2.x.