Support authentication mechanism negotiation.  If the authentication mechanism is unspecified, the driver will use the most secure mechanism based on the server version.
Currently this is SCRAM-SHA-1 for server version >= 2.8, and MONGODB_CR for earlier server versions.

JAVA-1461
Added support for the listIndexes command

JAVA-1456
Added ListCollections command support getCollectionNames

JAVA-1455