* handwired/arrow_pad: layout macro and keymap refactor
- Layout macros moved from the keymaps to arrow_pad.h.
- LAYOUT_pad21 refactored to only accept keys that are physical present (no KC_NO entries required in keymap)
- Keymaps now use #include QMK_KEYBOARD_H
- Keymaps refactored to use process_record_user function (from action_get_macro)
* handwired/arrow_pad: Readme cleanup
Fixed the make commands and updated the layout macro.
* handwired/arrow_pad: Configurator support
