Add a tree editor for the whole hierarchy

Did this patch ever get added? It would make my life a LOT easier, but it doesn't seem like it got into the code, and now we are up version 3.3, so I doubt the patch still works.

I'm trying the patch in #12 now and it works well, at least for my limited use case. Since it's been a few years since it landed, and since the code changes themselves are concise and straightforward, I'm willing to mark this as RTBC.

Would still like to see some tests here

Created an issue fork and rerolled patch from #12 so it will apply to the latest 3.x and 3.3.10.

Still needs tests.

Is this opt in? Slightly concerned it could break our 'Children' tab when we have a `5 / 70 / 10 / 6` type hierarchy. (format of child summary in views).

This is just for editing the tree @nterbogt i think it won't effect that rendering.

It's one and the same... I've been working on the code for the Children tab in 5.x quite a bit :)

Reroll for 3.3.11. Still no tests, sorry :(

I've also removed the depth limiter from this patch as the issue was fixed by #3212448: Error when adding children below a depth of nine with microsite enabled →

inregards2pluto → changed the visibility of the branch 3.x to hidden.

I've pushed a commit to the existing MR for this work that applies the latest rerolled patch (3178313-tree-editor-24.diff). I also synced the branch with the forked 3.x branch.

I'm working on refactoring the ReorderChildrenFunctionalTest.php to test the patch functionality of being able to reorder the full tree. Separately, it looks like there's a phpunit test failing right now? I haven't parsed it apart, but it would be helpful if someone more familiar with the existing testing pipeline could offer some guidance on what might be happening there.