Fixes #1: ShareUrl: Dynamically created by client

Made the client contruct the shareUrl, to account for the use of proxies. Now the server sends the client only its ip, and the endpoint. The client then constructs the shareUrl link by getting the same url he is connected to. If the url is "localhost" though, he will use the "ip" sent by the server (since most people connect with "localhost", but want to have a function share link).

js/src/main/scala/cs214/webapp/client/Pages.scala

@@ -275,7 +275,7 @@ case class AppPage(appId: AppId, uiId: UIId, instanceId: InstanceId, userId: Use
         .replace("{{hostName}}", hostName + (if port.nonEmpty then f":$port" else ""))
         .replace("{{userId}}", URLEncoder.encode(userId, "UTF-8"))
       val shareUrlHost = 
-        if hostName == "localhost" then appInfo.hostAddress else hostName
+        if (hostName == "localhost" || hostname == "127.0.0.1") then appInfo.hostAddress else hostName
       
       val shareUrl = f"$hypertextProtocol://${shareUrlHost}${if port.nonEmpty then f":$port" else ""}${appInfo.shareSubUrl}"