Dynamically populate LocalAddress based on HTTP request

Support populating the LocalAddress field in the system info
endpoint based on the x-forwarded-host and x-forwarded-proto header.

The x-forwarded-host header must contain both the host and port for
the url to be properly constructed.

Behind network configuration option that is disabled by default.

Jellyfin.Networking/Configuration/NetworkConfiguration.cs

@@ -226,5 +226,10 @@ namespace Jellyfin.Networking.Configuration
         /// Gets or sets the known proxies. If the proxy is a network, it's added to the KnownNetworks.
         /// </summary>
         public string[] KnownProxies { get; set; } = Array.Empty<string>();
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the published server uri is based on information in HTTP requests.
+        /// </summary>
+        public bool EnablePublishedServerUriByRequest { get; set; } = false;
     }
 }