add a feature test that ensures SSL configuration

Please add a feature test to ensure SSL can be configured and used.

Currently this can be configured by setting environmental properties on com.couchbase.client.core, but this should be easier to configure such that it fits into other frameworks such as Kafka connect. This could be based on the connection string, for instance.

Sergey Avseyev: Can you add the properties that need to be defined as a workaround?