Keyboard: Infinity60 refactor, Configurator support and readme update (#4707)

Keyboard: Infinity60 refactor, Configurator support and readme update (#4707)

* Infinity60: refactor

- infinity60.h / keymap.c
  - renamed layout macro to LAYOUT_60_ansi_split_bs_rshift; removed layout macro alias
  - updated to #pragma once
  - keymaps now use #include QMK_KEYBOARD_H
  - keymaps/jpetermans/config.h updated to #pragma once
  - keymaps/jpetermans/rules.mk deleted (complete contents were deprecated make instructions)

* Infinity 60%: Configurator support

* Infinity60: readme update

Updated the Docs links.

* Infinity60: bugfix depariel keymap

Had a typo.

* Infinity60: edit matrix.c

per @drashna

- https://github.com/qmk/qmk_firmware/pull/4707#issuecomment-449540676