Rename config properties

Prefix all config property names with "couchbase." to avoid conflicts and to make it clear the property applies to the Couchbase connector. After the "couchbase." prefix, use the lowerCamelCase convention.

For example: "couchbase.document.id" becomes "couchbase.documentId"

and "couchbase.stream_from" becomes "couchbase.streamFrom".

The full table of old and new names will be included in the 4.0 migration guide.