KBDfans Bella Soldered Layout Macro Additions (qmk#20691)

* add matrix_diagram.md

* info.json: apply friendly formatting

* add LAYOUT_ansi_rwkl_split_bs

* add LAYOUT_ansi_rwkl

* add LAYOUT_ansi_wkl_split_bs

* add LAYOUT_ansi_wkl

* add LAYOUT_iso_rwkl_split_bs

* add LAYOUT_iso_rwkl

* add LAYOUT_iso_wkl_split_bs

* add LAYOUT_iso_wkl

* refactor keymaps

- use four-space indent
- add layer indices
- grid-align keycodes