handwired/space_oddity: refactor, Configurator support and readme cleanup (#4977)

* handwired/space_oddity: refactor

- config.h: updated to use #pragma once include guard
- rules.mk: replace `?=` with `=`
- space_oddity.h:
  - updated to use #pragma once include guard
  - layout macro KEYMAP renamed to LAYOUT
- default keymap:
  - updated to use #include QMK_KEYBOARD_H
  - replace references to Planck keycodes
  - replace fn_actions-powered layer switch keycode
  - rebuild keymap block comments
  - keymap layers now use short-form keycodes
  - refactor action_get_macro keycodes into process_record_user

* handwired/space_oddity: Configurator support

* handwired/space_oddity: readme cleanup

- update readme to better conform with QMK template
- fixed the make command.

keyboards/handwired/space_oddity/space_oddity.h

@@ -1,9 +1,8 @@
-#ifndef KB_H
-#define KB_H
+#pragma once
 
 #include "quantum.h"
 
-#define KEYMAP( \
+#define LAYOUT( \
 	K000,       K002,       K004,       K006,       K008,       K010, K011, \
 	K100, K101, K102, K103, K104, K105, K106, K107, K108, K109, K110, K111, \
 	K200, K201, K202, K203, K204, K205, K206, K207, K208, K209, K210, K211, \
@@ -18,5 +17,3 @@
 	{ K400,  K401,  K402,  K403,  K404,  K405,  K406,  K407,  K408,  K409,  K410,  K411 }, \
 	{ K500,  K501,  K502,  K503,  KC_NO, K505,  KC_NO, K507,  K508,  K509,  K510,  K511 }  \
 }
-
-#endif