Provide an API to ContainerProvider to allow ServiceLoader results to be filtered / prioritised / sorted

This will require a minimum of Java 9. Then we can use `ServiceLoader.stream()` and filter / sort the results. I'm leaning towards sort rather than filter.

Start by reading the ContainerProvider API and the Java 9 ServiceLoader.stream() API. Determine the intended API shape for filtering, prioritising, or sorting provider results, including whether sorting should replace filtering. Done means ContainerProvider exposes the agreed capability and the Java 9 minimum is documented.

Written by the indexing model from the issue text.