[Keyboard] Add the Octopad (#9946)

* Create Alter folder

* Revert "Create Alter folder"

This reverts commit 361103b821dbb22957b66cdedb0d11f996def71c.

* Add octopad folder

* Added a new keyboard, the Octopad

* Edited files based on requested changes

* Moved encoder code in keyboard level

* Updated the readme

* Corrected the rows and columns of encoders on config.h

* Changed the Vendor ID to D812 since the first one was already taken

* Added support for ast1109MLTRQ speakers

* Increased number of layers to 8 on VIA keymap

* Edited files based on comments

* Edited rules.mk as per comment

* Edited readme.md as per comment

keyboards/nightly_boards/octopad/encoder_action.h

@@ -0,0 +1,21 @@
+/* Copyright 2020 Neil Brian Ramirez
+ *
+ * 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 3 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/>.
+ */
+
+#include "quantum.h"
+
+void encoder_action_unregister(void);
+
+void encoder_action_register(uint8_t index, bool clockwise);