GH-2932: Sanitize sensitive data on bindings endpoint

Resolves https://github.com/spring-cloud/spring-cloud-stream/issues/2932

Spring Boot provides `SanitizingFunction` to allow the applicaitons to clear out
sensitive data when using certain actuator endpoints. This feature can be
extended to custom endpoints as well. Enable the bindings actuator endpoint
to sanitze sensitive data based on user-provided logic in `SantizingFuction`
beans in the application.

docs/modules/ROOT/pages/spring-cloud-stream/binding_visualization_control.adoc

@@ -82,3 +82,24 @@ You can also stop, start, pause, and resume individual bindings by posting to th
 NOTE: `PAUSED` and `RESUMED` work only when the corresponding binder and its underlying technology supports it. Otherwise, you see the warning message in the logs.
 Currently, only Kafka and [Solace](https://github.com/SolaceProducts/solace-spring-cloud/tree/master/solace-spring-cloud-starters/solace-spring-cloud-stream-starter#consumer-bindings-pauseresume) binders supports the `PAUSED` and `RESUMED` states.
 
+[[sanitize-sensitive-data]]
+=== Sanitize Sensitive Data
+
+When using the binding actuator endpoint, it is sometimes critical to sanitize any sensitive data such as user credentials, information about SSL keys, etc.
+To achieve this, end user applications can provide a `SanitizingFunction` from Spring Boot as a bean in the application.
+Here is an example to scramble the data when providing a value for Apache Kafka's `sasl.jaas.config` property.
+
+```
+@Bean
+public SanitizingFunction sanitizingFunction() {
+	return sanitizableData -> {
+		if (sanitizableData.getKey().equals("sasl.jaas.config")) {
+			return sanitizableData.withValue("data-scrambled!!");
+		}
+		else {
+			return sanitizableData;
+		}
+	};
+}
+```
+