Follow up to the support for Golang in Export to Language:

• the URL in ApplyURI is always "localhost", in the other languages we pass that value as a variable somehow so it reflects the current connection
• the import: "go.mongodb.org/mongo-driver/mongo/options" is missing with the generated code
• Missing struct initialization: primitive.Null -> primitive.Null{} and primitive.Undefined -> primitive.Undefined{}
• The generated code makes vet complain about: "go.mongodb.org/mongo-driver/bson/primitive.E composite literal uses unkeyed fields"