common: Move settings to common from core.

- Removes a dependency on core and input_common from common.

src/input_common/touch_from_button.cpp

@@ -2,8 +2,8 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include "common/settings.h"
 #include "core/frontend/framebuffer_layout.h"
-#include "core/settings.h"
 #include "input_common/touch_from_button.h"
 
 namespace InputCommon {