INT-2738 Add Missing getComponentType() Methods

JIRA: https://jira.spring.io/browse/INT-2738

Add a `getComponentType()` method for all handlers,
message producers, and message sources that implement
`NamedComponent` (see `SPCA.getComponentType()`).

Add rome as an optional dependency - STS complained
because AtomFeedHttpMessageConverter has a dependency
on it.

spring-integration-xml/src/main/java/org/springframework/integration/xml/transformer/MarshallingTransformer.java

@@ -74,6 +74,11 @@ public class MarshallingTransformer extends AbstractTransformer {
 		this.extractPayload = extractPayload;
 	}
 
+	@Override
+	public String getComponentType() {
+		return "xml:marshalling-transformer";
+	}
+
 	@Override
 	public Object doTransform(Message<?> message) {
 		Object source = (this.extractPayload) ? message.getPayload() : message;

spring-integration-xml/src/main/java/org/springframework/integration/xml/transformer/UnmarshallingTransformer.java

@@ -81,6 +81,10 @@ public class UnmarshallingTransformer extends AbstractPayloadTransformer<Object,
 		this.alwaysUseSourceFactory = alwaysUseSourceFactory;
 	}
 
+	@Override
+	public String getComponentType() {
+		return "xml:unmarshalling-transformer";
+	}
 
 	@Override
 	public Object transformPayload(Object payload) {

spring-integration-xml/src/main/java/org/springframework/integration/xml/transformer/XPathTransformer.java

@@ -106,6 +106,11 @@ public class XPathTransformer extends AbstractTransformer {
 		this.converter = converter;
 	}
 
+	@Override
+	public String getComponentType() {
+		return "xml:xpath-transformer";
+	}
+
 	@Override
 	protected Object doTransform(Message<?> message) throws Exception {
 		Node node = this.converter.convertToNode(message.getPayload());