Upgrade to TestContainers 1.15.2

What's Changed
What 1984 means to you? To us, this number means PR #1984, one of the oldest PRs we had open and... finally merged! Thanks to an amazing contribution by @seglo, we now provide an example of testing Kafka clusters where multiple KafkaContainers are connected into one network. Try it!
Another "old" PR is #3180 by @oussamabadr. Those of you who run Selenium tests with Testcontainers will appreciate this newly added option to use (scrollable!) MP4 format instead of FLV.
The connection with Ryuk (our watchdog sidecar container) now sets the socket timeout and retries the failures - helps with some rare networking edge cases. (#3682) @diegolovison
The logs consumer no longer adds extra new lines thanks to #3752 by @perlun
Locally built images no longer get affected by the hub.image.name.prefix setting! (#3666) @reda-alaoui
Jackson dependency is now forced to an older version to help with NoClassDefFoundError (com/fasterxml/jackson/annotation/JsonMerge).
And more!