database::create_view was deprecated in 3.4, and it will be removed in 3.5 (CXX-1931).  In the deprecation notes, it said:

To create a non-materialized view, use database::create_collection and pass "viewOn": "COLLECTION_NAME", "pipeline": [ ... stages ... ] in the bsoncxx::document::view_or_value collection_options.

But we don't provide a nice way to pass a bson document as the options to create_collection.  Currently, users will have to build their other create_collection options using the strongly-typed helper methods, then convert their options to a bson document, then append additional values for "viewOn" and "pipeline."  Add a way to support creating a view with create_collection.