Move CLI integration tests into spring-boot-cli

Use `maven-failsafe-plugin` to run CLI integration tests as part of
the `spring-boot-cli` project, removing the need for
`spring-boot-cli-integration-tests`.

spring-boot-cli/pom.xml

@@ -154,6 +154,9 @@
 			</resource>
 		</resources>
 		<plugins>
+			<plugin>
+				<artifactId>maven-failsafe-plugin</artifactId>
+			</plugin>
 			<plugin>
 				<artifactId>maven-surefire-plugin</artifactId>
 				<configuration>
@@ -329,6 +332,24 @@
 					</execution>
 				</executions>
 			</plugin>
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>build-helper-maven-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>add-test-source</id>
+						<phase>process-resources</phase>
+						<goals>
+							<goal>add-test-source</goal>
+						</goals>
+						<configuration>
+							<sources>
+								<source>src/it/java</source>
+							</sources>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 		<pluginManagement>
 			<plugins>