Add a no-metadata JAR variant (#1643)

This adds a JAR target without included metadata. Third parties using this
variant may supply their own metadata via a custom MetadataLoader.

java/libphonenumber/pom.xml

@@ -42,11 +42,32 @@
       <plugin>
         <artifactId>maven-jar-plugin</artifactId>
         <version>3.0.2</version>
-        <configuration>
-          <archive>
-            <manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
-          </archive>
-        </configuration>
+        <executions>
+          <execution>
+            <id>default-jar</id>
+            <configuration>
+              <archive>
+                <manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
+              </archive>
+            </configuration>
+          </execution>
+          <execution>
+            <id>no-metadata</id>
+            <phase>package</phase>
+            <goals>
+              <goal>jar</goal>
+            </goals>
+            <configuration>
+              <classifier>no-metadata</classifier>
+              <archive>
+                <manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
+              </archive>
+              <excludes>
+                <exclude>com/google/i18n/phonenumbers/data/*</exclude>
+              </excludes>
+            </configuration>
+          </execution>
+        </executions>
       </plugin>
       <plugin>
         <groupId>org.codehaus.mojo</groupId>