Integration Testing for Sinker

Currently there is no meaningful testing for the Sinker controller code. Given the limitations of the kube.rs crate it seems like the easiest and most practical way to get this test coverage would be to simply write some integration tests that run against a kind cluster which can be spun up and torn down either as part of the test code or using automation that wraps the tests.

See https://kube.rs/controllers/testing/ for more info.