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/test-samples/integration_auto.groovy

@@ -0,0 +1,21 @@
+package com.example
+
+@SpringBootApplication
+@SpringBootTest(classes=RestTests, webEnvironment=WebEnvironment.RANDOM_PORT)
+class RestTests {
+
+	@Autowired
+	TestRestTemplate testRestTemplate;
+
+	@Test
+	void testHome() {
+		assertEquals('Hello', testRestTemplate.getForObject('/', String))
+	}
+
+	@RestController
+	static class Application {
+		@RequestMapping('/')
+		String hello() { 'Hello' }
+	}
+
+}