[Keyboard] add macro pad "Shiro" (#6338)

* add keyboard new macro pad "Kuro"

* change main readme.md

* remove not used code from default/keymap.c

* Remove unnecessary code

* Supports info.json

* removed back slash and not used functions.

* update at product link. add japanese messages.

keyboards/shiro/shiro.h

@@ -0,0 +1,41 @@
+/* Copyright 2019 T.Shinohara
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#include "quantum.h"
+
+/* This a shortcut to help you visually see your layout.
+ *
+ * The first section contains all of the arguments representing the physical
+ * layout of the board and position of the keys.
+ *
+ * The second converts the arguments into a two-dimensional array which
+ * represents the switch matrix.
+ */
+#define LAYOUT( \
+    k00, k01, k02, \
+    k10, k11, k12, \
+    k20, k21, k22, \
+    k30, k31, k32, \
+    k40, k41, k42 \
+) \
+{ \
+    { k00, k01, k02 }, \
+    { k10, k11, k12 }, \
+    { k20, k21, k22 }, \
+    { k30, k31, k32 }, \
+    { k40, k41, k42 } \
+}