* Allow for provision of a Testcontainer instance
Testcontainers provides many different container implementations that
can be very useful. This simple change allows callers to provide their
own, premade container instance so consumers can flexibly choose their
container type. If no container instance is supplied, then
clj-test-containers falls back to its original behavior.
* Extract function
* Cleanup, ensure Clojure types instead of Java types
Co-authored-by: Tim Zöller <mail@tim-zoeller.de>
