add a simple side for the extended frame pieces

I'm thinking the "extended" pieces become the only pieces soon, this is
one step closer to it

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

src/frames/pieces/extended/side.scad

@@ -0,0 +1,23 @@
+/*
+ * SPDX-FileCopyrightText: © 2024 Brian S. Stephan <bss@incorporeal.org>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+include <parameters.scad>
+include <components.scad>
+use <front-or-back.scad>
+
+module side_frame_piece() {
+	piece_width = panel_support_width+frame_wall+frame_mount_column_width;
+	difference() {
+		// side piece is left/right agnostic
+		frame();
+		// minus the top and bottom
+		front_or_back_frame_piece();
+		rotate([180, 0, 0]) front_or_back_frame_piece();
+		// and just chop out the rest of the frame
+		translate([piece_width, 0, 0]) cube([frame_x, frame_y+1, frame_z+1], center=true);
+	}
+}
+
+side_frame_piece();