[Keyboard] Move Hillside out of handwired (#18751)

Co-authored-by: mmccoyd <mmccoyd@cs.berkley.edu>

keyboards/hillside/48/keymaps/default/config.h

@@ -0,0 +1,9 @@
+// Copyright 2022 Michael McCoyd (@mmccoyd)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+// Some boards have issues detecting handedness using the vbus voltage,
+// such as Elite-C v3, but not v3.1 on, and apparently some ProMicro boards.
+// For those boards, use usb detection instead.
+// #define SPLIT_USB_DETECT