Improvements in clickhouse plugin (#1031)
Improvements in clickhouse plugin (#1031)

- Add username/password authentication support for clickhouse.
- Add support to first create the required table.

Signed-off-by: Pradeep Chhetri <da29e79783ce5c0cfdb09fdec3d4e94d1f4520ad@gmail.com>

Signed-off-by: Pradeep Chhetri <da29e79783ce5c0cfdb09fdec3d4e94d1f4520ad@gmail.com>
riemann/riemann,riemann/riemann