New settings/config item type

[codente]

Right now, we support theme customizer settings but no other settings. We discussed converting customizer settings into a new item type that would support different types of settings. So customizer could be one subtype of the new item type, and so can BB settings (and possibly later down the road FSE settings and even maybe ACF settings)

[brentjett]

Has the FSE interface exposed a way to add settings? I remember looking but couldn't find it a few months back.