[6.x] Allow multi-column config layout in user globals

[daun]

Enable the as-config prop though a new Layout Mode setting on the Global Set Config. Very useful for settings-type screens to save vertical space. Currently, they are only available to the core and addons (via PublishForm::make()->asConfig()).

Closes statamic/ideas#1470

Usage

# content/globals/settings.yaml
title: Settings
layout_mode: multi_column

Example

[jasonvarga]

@jackmcdade This one requires a call from you first. Is this something we even want to support? Or do you want to keep the alternate layout for just config?

And if yes, why only globals? We could probably easily allow you to opt into this layout for entries, terms, etc.

cc @jaygeorge

[jackmcdade]

@jasonvarga I'm gonna pull it across all the areas and see how it feels. I would lean towards not doing it, but sometimes I do feel like I'd like alt layouts for certain types of content... Let's see where this goes. 🤘

[jackmcdade]

Okay so I really like this, but ONLY for Globals. It makes Entries and Terms look ridiculous. I'm gonna wire up a CP UI to toggle it on and off per-global set, do a once over on the PR, and then I say let's merge it. Thanks @daun!

[daun]

Nice. I like that it's becoming much more sophisticated now, fancy UI toggles and all :) Great stuff!