Support for experimental reactiver starter

This commit adds support for the experimental reactive starter. When
that starter is selected, the version of Spring Framework and Reactor are
automatically overridden and the java version is forced to 1.8

This starter includes an additional BOM that provides dependency
management for reactive-related dependencies (typically netty).

initializr-service/pom.xml

@@ -24,6 +24,23 @@
 			<groupId>io.spring.initializr</groupId>
 			<artifactId>initializr-actuator</artifactId>
 		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>io.spring.initializr</groupId>
+			<artifactId>initializr-generator</artifactId>
+			<type>test-jar</type>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>xmlunit</groupId>
+			<artifactId>xmlunit</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<build>