Disable javadoc generation by default, enable on ci

It javadoc:jar is run as part of release by maven-release-plugin, so it must pass ci, but it annoying locally

travis/settings.xml

@@ -263,6 +263,7 @@ under the License.
 
       <properties>
         <runelite.tomcat.url>http://api.runelite.net/manager/text</runelite.tomcat.url>
+        <maven.javadoc.skip>false</maven.javadoc.skip>
       </properties>
     </profile>
   </profiles>