DRILL-4882 - Support for MongoDB Direct Connection to a node in a Replica Set.

[tgrall]

See issue DRILL-4882

In some case, for analytics the applicatio, Drill, has to connect to node directly without access the replica set or shard globally.

The new configuration option direct-connection true|false allows drillbit to be directly connected to a node.

References:

• Connection String
• Direct Connection term