To enable the creation of default expectations that are generic across all tests or mocking scenarios a class can be specified
to initialize expectations in the MockServer, this class must implement org.mockserver.initialize.PluginExpectationInitializer interface,
the initializeExpectations(MockServerClient mockServerClient) method will be called once the MockServer has been started (but ONLY
if serverPort has been set), however it should be noted that it is generally better practice to create all expectations locally in
each test (or test class) for clarity, simplicity and to avoid brittle tests