Add script to help with doc (#6430)

* Add script to help with doc

* better

.github/scripts/find-all-config-properties.sh

@@ -0,0 +1,5 @@
+#!/bin/bash -e
+
+grep -Pohr --include '*.java' --exclude-dir=test \"otel.instrumentation.[^\"]+\" \
+  | grep -v otel.instrumentation.internal \
+  | sort -u