Install available sources with the SDK product

Currently only some sources are included in the SDK product these are
those that explicitly specified in source features. As removing more and
more third party dependencies from features, they will also vanish from
source features and therefore missing in the SDK product. Beside that,
managing source features itself is a tedious task.

This enables the <installSources> option for the SDK product that will
install any available source with a bundle automatically.

eclipse.platform.releng.tychoeclipsebuilder/eclipse.platform.repository/pom.xml

@@ -382,6 +382,7 @@ UNmHBQdtflW5G1L5fQggWG7V
             </goals>
             <configuration>
               <profile>SDKProfile</profile>
+              <installSources>true</installSources>
             </configuration>
           </execution>
           <execution>
@@ -514,4 +515,4 @@ UNmHBQdtflW5G1L5fQggWG7V
       </build>
     </profile>
   </profiles>
-</project>
+</project>