Ákos Ádám Medgyes

- fixes #387 Checklist: - [x] Add tests that demonstrate the correct behavior of the change. Tests should fail without the change. - [x] Add or update relevant docs, in...

**Describe the bug** Username,password is not mandatory for clickhouse. If they are not set then the current implementation sends a `Basic Og==` as the Authorization header and it fails. **To...