Add support for Spring Rabbit (via Spring AMQP) to Boot

- If RabbitTemplate is on the classpath, turn on autodetection.
- Create a RabbitTemplate, a Rabbit ConnectionFactory, and a RabbitAdmin is spring.rabbitmq.dynamic:true
- Enable some **spring.rabbitmq** properties like host, port, username, password, and dynamic
- Add tests to verify functionality
- Add Groovy CLI functionality. Base it on @EnableRabbitMessaging. Add spring-amqp to the path.
- Create rabbit.groovy test to prove it all works.
- Make Queue and TopicExchange top-level Spring beans in rabbit.groovy test script

spring-boot-cli/src/main/resources/META-INF/services/org.springframework.boot.cli.compiler.CompilerAutoConfiguration

@@ -1,6 +1,7 @@
 org.springframework.boot.cli.compiler.autoconfigure.SpringBootCompilerAutoConfiguration
 org.springframework.boot.cli.compiler.autoconfigure.SpringMvcCompilerAutoConfiguration
 org.springframework.boot.cli.compiler.autoconfigure.SpringBatchCompilerAutoConfiguration
+org.springframework.boot.cli.compiler.autoconfigure.RabbitCompilerAutoConfiguration
 org.springframework.boot.cli.compiler.autoconfigure.ReactorCompilerAutoConfiguration
 org.springframework.boot.cli.compiler.autoconfigure.JdbcCompilerAutoConfiguration
 org.springframework.boot.cli.compiler.autoconfigure.JmsCompilerAutoConfiguration

spring-boot-cli/src/main/resources/META-INF/springcli.properties

@@ -4,6 +4,7 @@ reactor.version: ${reactor.version}
 spring.version: ${spring.version}
 spring-batch.version: ${spring-batch.version}
 spring-boot.version: ${project.version}
+spring-rabbit.version: ${spring-rabbit.version}
 spring-security.version: ${spring-security.version}
 spring-integration.version: ${spring-integration.version}
 spring-integration-groovydsl.version: ${spring-integration-groovydsl.version}