Add options for new Server Discovery and Monitoring engine to example for version 3.6 of the Node driver

Description

Following the Node.js Connection Guide will return a Deprecation Warning:

(node:98468) DeprecationWarning: current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.

Passing the following to the MongoClient resolves the warning:

,{ useNewUrlParser: true, useUnifiedTopology: true }

Scope of changes

Cut a 3.6 branch and change the connection guide and all examples to include connection options that became default in 4.0

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)