Adds property to disable forwarded-request-headers-filter

Fixes gh-3238

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/GatewayServerMvcAutoConfiguration.java

@@ -82,6 +82,8 @@ public class GatewayServerMvcAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean
+	@ConditionalOnProperty(prefix = GatewayMvcProperties.PREFIX, name = "forwarded-request-headers-filter.enabled",
+			matchIfMissing = true)
 	public ForwardedRequestHeadersFilter forwardedRequestHeadersFilter() {
 		return new ForwardedRequestHeadersFilter();
 	}

spring-cloud-gateway-server-mvc/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -0,0 +1,10 @@
+{
+  "properties": [
+    {
+      "name": "spring.cloud.gateway.mvc.forwarded-request-headers-filter.enabled",
+      "type": "java.lang.Boolean",
+      "description": "Enables the forwarded-request-headers-filter.",
+      "defaultValue": "true"
+    }
+  ]
+}