client-report/src/util/url.js returns the wrong report URL for non-polis / xip.io sites

[midgleyc]

client-report/src/util/url.js checks the domain for a variety of included strings, returning fixed hostnames if matched. If you're not running on a proper pol.is domain, or xip.io, it returns localhost. This breaks reports. For example, see this report -- if you check the console you can see it's trying to access localhost, which is wrong.

If not polis assume localhost:

if ((-1 === document.domain.indexOf("pol.is")) && (-1 === document.domain.indexOf("polis.io"))) {    
    urlPrefix = localhost;    
}

Fix only for specific URLs:

if (0 === document.domain.indexOf("192.168") || document.domain.includes(".xip.io")) {               
  urlPrefix = "http://" + document.location.hostname + ":" + document.location.port + "/";           
}

I think the correct URL is specified in polis.config.js as SERVICE_URL, but even always having a fallback would be useful.