FJLabs Polaris Layout Additions and Touch-Up (qmk#20622)

* add matrix_diagram.md

* refactor keymaps

* fix Configurator implementation

The original C-based code had an off-by-one error in the key sequence, that was then converted in data-driven configurator without being corrected.

* info.json: apply friendly formatting

* add LAYOUT_60_ansi_split_bs_rshift

* add LAYOUT_60_ansi

* add LAYOUT_60_tsangan_hhkb

* add LAYOUT_60_ansi_tsangan

* add LAYOUT_60_iso_split_bs_rshift

* add LAYOUT_60_iso

* add LAYOUT_60_iso_tsangan_split_bs_rshift

* add LAYOUT_60_iso_tsangan

* enable Community Layout support

* edit keyboard maintainer