[Keyboard] add treeadstone48 (#5405)

* Keyboard: add treeadstone48

* rename layout defines

* Use of pragma once

* move common include code

* fixed info.json

* change keymap layout from kc to normal

* fix alpha revision keymap

* fixed info.json

* remove USE_Link_Time_Optimization

keyboards/treadstone48/rev1/serial_config.h

@@ -0,0 +1,8 @@
+//// #error rev2 serial config
+
+#ifndef SOFT_SERIAL_PIN
+/* Soft Serial defines */
+#define SOFT_SERIAL_PIN D2
+
+#define SERIAL_USE_MULTI_TRANSACTION
+#endif