Introduce option to disable result set for DDL queries for JDBC connection

There are some tools (Unica, dBeaver, TalenD) that do not expect to obtain result set on CTAS query. As a result the query gets canceled. Hive, on the other hand, does not return result set for the query and these tools work well.

To improve Drill's integration with such tools a session option `exec.return_result_set_for_ddl` is introduced. If the option is enabled (set to `true`) Drill's behaviour will be unchanged, i.e. a result set will be returned for all queries. If the option is disabled (set to `false`), CTAS, CREATE VIEW, CREATE FUNCTION, DROP TABLE, DROP VIEW, DROP FUNCTION, USE schema, SET option, REFRESH METADATA TABLE queries will not return result set but updateCount instead.

The option affects JDBC connections only.