[Keyboard] nullbitsco/nibble Configurator rework (qmk#10814)

* nullbitsco/nibble: rework LAYOUT_all

... and update via keymap accordingly.

* compress info.json LAYOUT_all tree

Only changes the white space.

* rebuild info.json LAYOUT_all tree

Note: this commit makes the visual layout the ANSI layout with a split left Shift, instead of being the same as the ISO layout.

* unify code styles

Make logically-unchanged code blocks similar in appearance to logically-changed blocks.

* correct LAYOUT_iso key sequence

Move ISO Enter's object to its proper place.