Link to latest 6.x version of JavaDoc, remove broken links (#583)

Author: Simran-B

README.md

@@ -13,6 +13,4 @@ The official [ArangoDB](https://www.arangodb.com/) Java Driver.
 - [ChangeLog](ChangeLog.md)
 - [Examples](src/test/java/com/arangodb/example)
 - [Examples Async](src/test/java/com/arangodb/async/example)
-- [Tutorial](https://www.arangodb.com/docs/stable/drivers/java-tutorial.html)
-- [Documentation](https://www.arangodb.com/docs/stable/drivers/java.html)
-- [JavaDoc](http://arangodb.github.io/arangodb-java-driver/)
+- [JavaDoc](https://javadoc.io/doc/com.arangodb/arangodb-java-driver/6.25.0/index.html)