UUIDGenerator recorder

Continuation of PR #34 : added the missing `GivenUUIDGeneratorRecorder` impl for a `GivenUUIDGenerator` :-)

Note that I took a different type of implementation than `GivenJongoCollectionRecorder`, using ThreadLocalized Observers for callbacks after uuid generation.
This way, we can register an observer during the `recordIn()` (and clean it in the `AutoCloseable.close()`)