Make parameter and objective classes slotted

[AdrianSosic]

Now that attrs==24.1.0 supports cached_property with slotted classes, we can finally enable slots for our parameter and objective classes.

[AdrianSosic]

Note: there was another issue which messed with our subclass detection mechanism, which has already be resolved but the fix has not yet been released. However, the checks should automatically pass once attrs 24.1.0 is available.

[AVHopp]

I guess there is not really a need for a proper and full review, this is just some maintenance right?

[Scienfitz]

deleted

[AdrianSosic]

@AVHopp @Scienfitz, FYI: I rebased and added one more commit since in the meantime we also had to make our Objective classes slotted ... a change that can be similarly reverted by this PR once the attrs support has been released

[AdrianSosic]

Again on hold until the following blocking issue gets resolved:
python-attrs/attrs#1325

[AdrianSosic]

Not happening much on the attrs side at the moment but potentially the problem becomes obsolete when switching to mkdocs, so let's keep it idling for a few more weeks...

[AVHopp]

@AdrianSosic - "a few more weeks" is over by half a year, any updates here?

[AdrianSosic]

@AdrianSosic - "a few more weeks" is over by half a year, any updates here?

Nothing I can do at the moment. I know that there is something happing due to changes in Python 3.14, but unclear if it will resolve the issue. And workarounds/fixes from our end would require waiting for the new docs. I'll close the issue now and will reconsider once there is a reason to do so