Remove ns/ts

Another modification to the mongo doc manager that removes the requisite for modifying documents that are being inserted into mongo. The _ts and ns fields are no longer inserted into the document. However if a document is already using _ts and ns fields it will overwrite them with oplog data and then this will remove them. It should be clear in the documentation that these fields will not survive transit by mongo connector, a more intense refactoring is needed to remove the dependency on these fields.

This now passes the unit tests as well. The mongo doc manager test was modified to make sure ns is always a field being passed into the oplog, as this will always be true in production