public static List<String> getPayloads() {
        return payloads;
    }
A simple servlet that pretends to be an API Management Gateway REST endpoint.  But
really all it does is record information about what requests it handled so that we
can do assertions in the tests.

@author eric.wittmann@redhat.com
manager/test/api/src/main/java/io/apiman/manager/test/server/MockGatewayServlet.java