[Keymap] crkbd/keymaps/rs: add rs keymap to corne keyboard and adapt others (#5181)

Update all my keymaps to work with 40 keys. Refactor code using
Userspace.

users/rs/rs.h

@@ -0,0 +1,50 @@
+#pragma once
+#include "quantum.h"
+
+enum layers {
+  _QWERTY,
+  _CODE,
+  _FN,
+};
+
+enum custom_keycodes {
+  CODE = SAFE_RANGE,
+  FN,
+  LPLT,
+  RPGT,
+  NEQL,
+#ifdef RGBLIGHT_ENABLE
+  RGBRST,
+#endif
+};
+
+#define KC_ KC_TRNS
+
+#define KC_ESCC MT(MOD_LCTL, KC_ESC)
+#define KC_ENTS MT(MOD_LSFT, KC_ENT)
+#define KC_LTGT LTGT // > or < with shift
+#define KC_LPLT LPLT // ( or < with shift
+#define KC_RPGT RPGT // ) or > with shift
+#define KC_NEQL NEQL // !=
+#define KC_CODE MO(_CODE)
+#define KC_BCOD LT(_CODE, KC_BSPC)
+#define KC_FN   MO(_FN)
+#define KC_RST  RESET
+#define KC_CTRA LCTL(KC_A)
+#define KC_CTRE LCTL(KC_E)
+#define KC_BLTG BL_TOGG
+#define KC_BLUP BL_INC
+#define KC_BLDN BL_DEC
+#define KC_BLBR BL_BRTG
+
+#ifdef RGBLIGHT_ENABLE
+#define KC_LRST RGBRST
+#define KC_LTOG RGB_TOG
+#define KC_LHUI RGB_HUI
+#define KC_LHUD RGB_HUD
+#define KC_LSAI RGB_SAI
+#define KC_LSAD RGB_SAD
+#define KC_LVAI RGB_VAI
+#define KC_LVAD RGB_VAD
+#define KC_LMOD RGB_MOD
+#endif