Move afterburner registration to dedicated method

This makes it a lot easier for frameworks that want
to use the module in GraalVM, to exclude Afterburner
(which does not work in GraalVM native image because
it generated classes at runtime)

Author: geoand

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/LambdaContainerHandler.java

@@ -81,9 +81,12 @@ public abstract class LambdaContainerHandler<RequestType, ResponseType, Containe
     private static ContainerConfig config = ContainerConfig.defaultConfig();
     private static ObjectMapper objectMapper = new ObjectMapper();
     static {
-        objectMapper.registerModule(new AfterburnerModule());
+        registerAfterBurner();
     }
 
+    private static void registerAfterBurner() {
+        objectMapper.registerModule(new AfterburnerModule());
+    }
 
 
     //-------------------------------------------------------------