Add Spring-based project contributors

This commit adds an optional module that gathers the opinions that are
used to generate a Spring Boot project.

Closes gh-340

Co-authored-by: Madhura Bhave <mbhave@pivotal.io>
Co-authored-by: Andy Wilkinson <awilkinson@pivotal.io>

initializr-generator/pom.xml

@@ -14,10 +14,6 @@
 	</properties>
 
 	<dependencies>
-		<dependency>
-			<groupId>io.spring.initializr.experimental</groupId>
-			<artifactId>initializr-generator-spring</artifactId>
-		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot</artifactId>
@@ -42,12 +38,6 @@
 			<optional>true</optional>
 		</dependency>
 
-		<dependency>
-			<groupId>io.spring.initializr.experimental</groupId>
-			<artifactId>initializr-generator</artifactId>
-			<scope>test</scope>
-			<type>test-jar</type>
-		</dependency>
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>
 			<artifactId>junit-jupiter</artifactId>

initializr-generator/src/main/java/io/spring/initializr/generator/io/text/Section.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2012-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.spring.initializr.generator.io.text;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+
+/**
+ * Define the section of a document that knows how to write itself.
+ *
+ * @author Stephane Nicoll
+ * @author Madhura Bhave
+ */
+public interface Section {
+
+	void write(PrintWriter writer) throws IOException;
+
+}

initializr-generator/src/main/java/io/spring/initializr/generator/io/text/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Support for textual resources.
+ */
+package io.spring.initializr.generator.io.text;