[bs-19] Add samples and CLI support for Spring Integration

$ cd spring-bootstrap-cli
    $ export SPRING_HOME=target
    $ src/main/scripts/spring run samples/integration.groovy

The big disadvantage at the moment is that there is no goo way to
detect Spring Integration in the AST (at least not as good as @Enable*).
So for now we are looking for @MessageEndpoint or a class name with
SpringIntegration in it.

[#48151147]

spring-bootstrap-samples/spring-bootstrap-integration-sample/src/main/resources/application.properties

@@ -0,0 +1,2 @@
+logging.file: /tmp/logs/app.log
+service.greeting: Hello

spring-bootstrap-samples/spring-bootstrap-integration-sample/src/main/resources/integration-context.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns:int="http://www.springframework.org/schema/integration"
+	xsi:schemaLocation="http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
+		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+
+	<int:channel id="input"/>
+	<int:service-activator input-channel="input" ref="sampleEndpoint"/>
+
+</beans>