Reintroduce the Quick effect selectors in the EQ preferences

[daschuer]

We need that to merge the effects_refactoring branch without a regression until the Skin effect GUI is in place. https://bugs.launchpad.net/mixxx/+bug/1948537

This does not revert to the 2.4 state where single effects where selected, It selects the effect chain presets and is fully aligned with the upcoming chain preset selectors in the skins.

[Be-ing]

I have already explicitly told you to not do this multiple times and explicitly told you to stop opening PRs for ideas which have already been rejected. This is counterproductive. If you want to help, then add the new widgets to the rest of the skins.

[daschuer]

It is quite natural that we have open differences in our opinions. In the sense of a good team spirit, I expect an open minded discussion about theses topics and not just close this PR without giving any reasons. I also think that your firm voice is not appropriate in this discussion.

I have outlined the main reason of "making progress and keeping Mixxx usable" here and I have also outlined my ideas in general in the bug report: https://bugs.launchpad.net/mixxx/+bug/1948537
With this merge, we have chance to take all the pressure form #4467