Relocate projects to spring-boot-project

Move projects to better reflect the way that Spring Boot is released.

The following projects are under `spring-boot-project`:

  - `spring-boot`
  - `spring-boot-autoconfigure`
  - `spring-boot-tools`
  - `spring-boot-starters`
  - `spring-boot-actuator`
  - `spring-boot-actuator-autoconfigure`
  - `spring-boot-test`
  - `spring-boot-test-autoconfigure`
  - `spring-boot-devtools`
  - `spring-boot-cli`
  - `spring-boot-docs`

See gh-9316

spring-boot-project/spring-boot-cli/samples/integration.groovy

@@ -0,0 +1,39 @@
+package org.test
+
+@Configuration
+@EnableIntegration
+class SpringIntegrationExample implements CommandLineRunner {
+
+	@Autowired
+	private ApplicationContext context;
+
+	@Bean
+	DirectChannel input() {
+		new DirectChannel();
+	}
+
+	@Override
+	void run(String... args) {
+		println()
+		println '>>>> ' + new MessagingTemplate(input()).convertSendAndReceive("World", String) + ' <<<<'
+		println()
+		/*
+		 *  Since this is a simple application that we want to exit right away,
+		 *  close the context. For an active integration application, with pollers
+		 *  etc, you can either suspend the main thread here (e.g. with System.in.read()),
+		 *  or exit the run() method without closing the context, and stop the
+		 *  application later using some other technique (kill, JMX etc).
+		 */
+		context.close()
+	}
+}
+
+@MessageEndpoint
+class HelloTransformer {
+
+	@Transformer(inputChannel="input")
+	String transform(String payload) {
+		"Hello, ${payload}"
+	}
+
+}