Modularize project structure

This commit splits the feature of Spring Initializr in several modules:

* `initializr-generator` is a standalone library that is responsible for
generating projects based on a `File` directory. It has a minimal set of
dependencies and is not web-related
* `initializr-web` provides the web integration (project generation,
meta-data, etc)
* `initializr-actuator` is an optional module that can be added to
support project-generation-specific statistics

Closes gh-214

initializr-generator/pom.xml

@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>io.spring.initalizr</groupId>
+		<artifactId>initializr</artifactId>
+		<version>1.0.0.BUILD-SNAPSHOT</version>
+	</parent>
+	<artifactId>initializr-generator</artifactId>
+	<name>Spring Initializr :: Generator</name>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.slf4j</groupId>
+			<artifactId>slf4j-api</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.codehaus.groovy</groupId>
+			<artifactId>groovy-templates</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.core</groupId>
+			<artifactId>jackson-databind</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.codehaus.groovy</groupId>
+			<artifactId>groovy</artifactId>
+			<scope>provided</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>xmlunit</groupId>
+			<artifactId>xmlunit</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-jar-plugin</artifactId>
+				<executions>
+					<execution>
+						<goals>
+							<goal>test-jar</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.codehaus.gmavenplus</groupId>
+				<artifactId>gmavenplus-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>