Keymap: Add userspace for @kageurufu (#4752)

* Add userspace for @kageurufu

* Remove custom keycodes for layer keys

Add some common defaults for my rules.mk

users/kageurufu/kageurufu.c

@@ -0,0 +1,12 @@
+#include "kageurufu.h"
+#include "quantum.h"
+#include "process_records.h"
+
+#ifdef RGBLIGHT_ENABLE
+  //Following line allows macro to read current RGB settings
+  extern rgblight_config_t rgblight_config;
+  rgblight_config_t backup_rgblight_config;
+
+  __attribute__((weak))
+  uint8_t RGBLIGHT_MODS[] = {0};
+#endif