Cloud Connection sample code update

Quoth AV: "As per the discussion in SDK meeting held on July 14th, it was deemed necessary that the SDK code samples for Cloud would be a bit outdated / behind."

& qoth RS:  "Please review the connection sample for Cloud on the Hello World page,
for changes in API, or any oddities,
and comment out the sslverify = false (so that we can suggest when it is appropriate,
and add in the relevant TLS certificate code
(we will add in downloading the Cloud Cert to the doc.
Thanks."

A connection and quick query against travel sample example is shown in pieces at https://docs.couchbase.com/c-sdk/current/hello-world/start-using-sdk.html#hello-couchbase

Adding the Cloud version as a complete example to https://github.com/couchbase/docs-sdk-c/tree/release/3.2/modules/devguide/examples/c as hello-cloud.cc, will enable us to pull it into that doc as a tabbed alternative.