Parallel execution of `MongoSink` operations

[paualarco]

Add new and more performant variants for the existing Sinks for the MongoDb connector that allows parallel execution of the operations. That would imply adding new signatures that expect a list of events instead of single ones.

The new signatures might be called same as the method but adding a Parallel suffix:

Example: cmd.sink.updateMany and (updateManyPar or updateManyBatch)