Refactoring to batch (#181)

The rationale of this pull request is to

* have more maintainable and granular code
* not maintain the custom made job engine
* allow the users to customize the defaults of the releaser more easy
* allow the users to create their own steps without the need to change any existing code
* allow the users to fully change the flows and tasks logic
* abstract underlying batch mechanism (Spring Batch) so it doesn't leak to production code
* allow parallelization of the release process and release tasks

projects/pom.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xmlns="http://maven.apache.org/POM/4.0.0"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<artifactId>releaser-projects</artifactId>
+	<version>1.0.0.BUILD-SNAPSHOT</version>
+	<packaging>pom</packaging>
+
+	<parent>
+		<groupId>org.springframework.cloud.internal</groupId>
+		<artifactId>releaser-parent</artifactId>
+		<version>1.0.0.BUILD-SNAPSHOT</version>
+		<relativePath>..</relativePath>
+	</parent>
+
+	<modules>
+		<module>spring-cloud</module>
+		<module>spring-cloud-stream</module>
+		<module>reactor</module>
+	</modules>
+
+</project>