GUI for Layout setup

[YamiYukiSenpai]

Is your feature request related to a problem? Please describe.
There's currently no GUI to setup a new layout or modify a pre-existing layout

Describe the solution you'd like
Not sure which one would be better, but it'd be great if it can be done in 2 places:

• from hovering to the top
• Similar to the builtin tiling where it'll open an overlay

Describe alternatives you've considered
Overriding the one that's built into Plasma or "merge" those 2 together.

Additional context

[YamiYukiSenpai]

I think a collaboration with whoever made Plasma's builtin custom tiling would be beneficial?
Right now, it has the opposite problem where we can't save any layouts
https://bugs.kde.org/show_bug.cgi?id=466019#c7