[Keyboard] Convert Corne Keyboard to Split Common (#6001)

* [Keyboard] Convert Corne Keyboard to Split Common

* Add VIA Support

* Makes sure that ol(e)d and new OLED implementation can't coexist

* Add licensing header to files

* Add changes based on feedback from foostan

* Fixes

keyboards/crkbd/rev1/common/common.c

@@ -0,0 +1,21 @@
+/*
+Copyright 2019 @foostan
+Copyright 2020 Drashna Jaelre <@drashna>
+
+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/>.
+*/
+
+#include "common.h"
+
+uint8_t is_master;