[Keyboard] QWERTYYdox refactor (#6446)

* Delete null key

`__` key in keymap.c doesn't actually exist on the physical hardware.
Removed key from keymap.c and removed its argument from the layout macro.

* Delete unused keycode aliases

* Replace layer index definitions with an enum

* Replace redundant numpad keycodes with native aliases

* Use native layer change keycodes instead of aliases

* Visually align the keycodes

It makes the keymap pretty.

* Correct Configurator layout data

* Clean up header files

- convert to pragma once include guard
- remove redundant definitions
- remove commented code blocks

* Delete LAYOUT_kc macro

Was copied from ergotravel; not valid for this keyboard.

* Consolidate rev1 rules.mk settings to keyboard level

Previous codebase enabled Backlight at keyboard level then disabled it at revision level.

* Delete unused rules

* Consolidate config.h settings from keymap level to keyboard level

* Modernize keyboard's config.h file

Aligns the keyboard-level config.h file more closely with the current QMK template for AVR keyboards.

keyboards/qwertyydox/rev1/rev1.h

@@ -1,12 +1,7 @@
-#ifndef REV1_H
-#define REV1_H
+#pragma once
 
 #include "qwertyydox.h"
 
-//void promicro_bootloader_jmp(bool program);
-#include "quantum.h"
-
-
 #ifdef USE_I2C
 #include <stddef.h>
 #ifdef __AVR__
@@ -15,12 +10,10 @@
 #endif
 #endif
 
-//void promicro_bootloader_jmp(bool program);
-
 #define LAYOUT( \
     L00, L01, L02, L03, L04, L05, L06,       R00, R01, R02, R03, R04, R05, R06, \
     L10, L11, L12, L13, L14, L15,            R10, R11, R12, R13, R14, R15, R16, \
-    L20, L21, L22, L23, L24, L25,            R20, R21, R22, R23, R24, R25, R26, \
+    L20, L21, L22, L23, L24, L25,                 R21, R22, R23, R24, R25, R26, \
     L30, L31, L32, L33, L34, L35, L36,       R30, R31, R32, R33, R34, R35, R36 \
     ) \
     { \
@@ -30,8 +23,6 @@
         { L30, L31, L32, L33, L34, L35, L36 }, \
         { R06, R05, R04, R03, R02, R01, R00 }, \
         { R16, R15, R14, R13, R12, R11, R10 }, \
-        { R26, R25, R24, R23, R22, R21, R20, }, \
+        { R26, R25, R24, R23, R22, R21, KC_NO, }, \
         { R36, R35, R34, R33, R32, R31, R30 } \
     }
-
-#endif