chore: Add script for cleaning build products (#899)

Author: jbelkins

scripts/clean_project.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+# Deletes known build products, caches, and temporary storage from the project.
+# Useful for reclaiming storage space or before archiving.
+#
+# Run this script from the root of the project.
+
+rm -rf .gradle
+rm -rf .build
+rm -rf build
+rm -rf smithy-swift-codegen/build