[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/keymaps/check/config.h

@@ -0,0 +1,19 @@
+/* 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
+
+// place overrides here