Move from AsyncInputStream handling to Publisher for GridFS.
UUID types require additional configuration setup to prevent errors while processing legacy (type 3) binary types. We still use type 3 as default but allow codec configuration for type 4 via Java and XML configuration.
Updated migration guide.
Original pull request: #823.
This change switches to the MongoDB 4.0 driver and introduces configuration options for com.mongodb.client.MongoClient.
The XML namespace changed from client-options to client-settings and removed already deprecated elements and attributes.
Imports are switched from single artifact uber jar to split imports for driver-core, -sync and -reactivestreams.
Deprecations have been removed.
Original pull request: #823.
