[Keyboard] Grid 600 Type 05 "PRESS" Cover Module (#6368)

* add grid600 type 5 press cover module

* Update keyboards/grid600/press/keymaps/default/keymap.c

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* remove unused custom keycode enum

keyboards/grid600/press/press.h

@@ -0,0 +1,32 @@
+/* Copyright 2019 mechmerlin
+ *
+ * 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, K03 \
+) { \
+	{ K00,   K01,   K02,   K03 }  \
+}