Add HTTPS support to integration tests

With no changes in the code we've started getting failures like this:

java.lang.AssertionError: Request not found exactly once, expected:<{
          "method" : "GET",
          "path" : "/case",
          "headers" : {
            "Host" : [ "registry.npmjs.org:80" ]
          },
          "secure" : false
        }> but was:<{
          "method" : "POST",
          "path" : "/-/npm/v1/security/audits/quick",

We probably just need to disable audits in the integration tests since we're mocking for proxy testing purposes.