Do not override hostname using X-Forwarded-For

Previously we used `X-Forwarded-For` header for extracting IP, however this
would override IP address, resulting in insconsistencies.
Now the IP is intact and expected to be processed in enrich as it should be.

core/src/main/scala/com.snowplowanalytics.snowplow.collector.core/Service.scala

@@ -203,7 +203,7 @@ class Service[F[_]: Sync](
 
   def extractIp(req: Request[F], spAnonymous: Option[String]): Option[String] =
     spAnonymous match {
-      case None    => req.from.map(_.toUriString)
+      case None    => req.remoteAddr.map(_.toUriString)
       case Some(_) => None
     }