[JAVA-1453] Applied 3.0 updated documentation to 2.13 code for the com.mongodb package

Used a combination of the same checkstyle rules that we use in 3.x and IntelliJ's inspections to track down missing public class/method documentation and apply changes from the 3.x branch.  Deprecated methods are not included, although if javadoc already existed for these methods/classes it has been retained.
It uses System.out and it's an undocumented public method. It's the same on 3.0 too, so I copied it over before I decided that turning on checkstyle was just not feasible.