Enable Maven build with m2e and tycho configurators installed in Eclipse

* Add Maven parent with tycho and P2 repo(s) for target definition
* Add Maven nature to all projects
* Add POM files with packaging eclipse-plugin , -feature, -repository
* Dedicated project for product definition
* Add configuration with default start levels to product definition

de.hftstuttgart.buildingphysics/.project

@@ -20,8 +20,14 @@
 			<arguments>
 			</arguments>
 		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.m2e.core.maven2Builder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
 	</buildSpec>
 	<natures>
+		<nature>org.eclipse.m2e.core.maven2Nature</nature>
 		<nature>org.eclipse.sirius.nature.modelingproject</nature>
 		<nature>org.eclipse.jdt.core.javanature</nature>
 		<nature>org.eclipse.pde.PluginNature</nature>

de.hftstuttgart.buildingphysics/pom.xml

+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>de.hftstuttgart.buildingphysics</artifactId>
+	<packaging>eclipse-plugin</packaging>
+	<name>Building Physics Catalog Model</name>
+
+	<parent>
+		<groupId>de.hftstuttgart</groupId>
+		<artifactId>buildingphysics.parent</artifactId>
+		<version>1.0.0-SNAPSHOT</version>
+		<relativePath>../de.hftstuttgart.buildingphysics.parent</relativePath>
+	</parent>
+	
+</project>
\ No newline at end of file