Effects refactoring

[daschuer]

This #2618 with its 957 comments, no longer usable in a reasonable way in the GitHunb GUI.

This branch is in a pre-mature state, but to make progress we have agreed to the following workaround proposed by @JoergAtGithub here: #2618 (comment)

May I propose a way out of this situation:
1.) @daschuer Adds FIXME comments to the code in this PR, where he found issues in his review before, which are still unsolved from his point of view
2.) As soon as anybody (@Be-ing or any other) commits to process all these FIXMEs in sense of daschuers review, @daschuer will press the merge button immediately
Until then, @Be-ing keeps this PR mergeable
3.) The dev who committed to process the FIXMEs, starts follow-up PRs for the FIXMEs

During the last days I have verified all my original review comments and fixed minor issues myself. Some work is already included here and some PRs are still pendig:
#4466, #4461, #4487, #4482, #4483, #4484, #4486
These PRs can be merged before merging this here or I will retarget them to main after merge.

Than I have created a number of Bugs

• lp1947570 Master EQ does not work in the effects_refactoring branch
• lp1947803 Usability issues in effect preferences dialog
• lp1947922 User decision is ignored when deleting an effect chain preset
• lp1947919 Warning Pop-Up missing when deleting a effect chain preset
• lp1947924 Effect chain preferences: Chain is not updated
• lp1947921 Effect chain preferences: It is possible to select one effect in each column.
• lp1947807 Single effect chains not visible after first start in effects_refactoring branch
• lp1947798 Allow effects without parameters in effects_refactoring branch
• lp1947908 Simple mode for QuickEffects in effects refactoring branch
• lp1947804 i18n Issue withe the effect chain presets in effects_refactoring branch
• lp1947615 DEBUG ASSERT in effects_refactoring branch
• lp1948535 Cluttered Tab order in the effect chain preferences
• lp1948536 No way to move effects and chains via keyboard in effect preferences
• lp1948540 DEBUG ASSERT (2) in effects_refactoring branch
• lp1948567 Empty chain selector after renaming
• lp1948600 Skin error in Tango skin with effects_refectoring banch
• lp1948606 Segfault after selecting a renamed effect in the QuickEffect chain selector

According to 2) of our commitment we need now one or more developers who are accepting the tasks to examine and fix the open issues that we are able to finally release this branch in a stable Mixxx 2.4. and update the manual accordingly.

Once we have such commitment, one of them may then merge it to main.

Thank you very much in advance.

[Be-ing]

Time is up.

[daschuer]

Thank you @Be-ing for merging this 11500 lines branch and taking back the responsibility to fix the pending issue and polish it for a release. Do you have a plan and schedule?
What are your next steps?

[ronso0]

@Be-ing Please document new controls in the manual

load_effect
load_preset
loaded_preset

[Be-ing]

We need to alias the old ControlObjects to coherent names before writing coherent documentation.