reorganize all the parts into subdirectories

src/ was getting pretty unreadable and I finally had time to do
something about it

Signed-off-by: Brian S. Stephan <bss@incorporeal.org>

src/panels/overhang/middle-dir_arc-plus-w-30mm-panel.scad

@@ -0,0 +1,18 @@
+/*
+ * SPDX-FileCopyrightText: © 2023 Brian S. Stephan <bss@incorporeal.org>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+include <parameters.scad>
+include <components.scad>
+
+module dir_arc_w_30mm_middle_overhang_panel() {
+	difference() {
+		panel_with_raised_overhang();
+		dir_arc_w_30mm();
+		rotate([0, 0, 180]) side_chopper();
+		side_chopper();
+	}
+}
+
+dir_arc_w_30mm_middle_overhang_panel();