Load Balancing: Move temporary files and make them configurable to allow for media upload when load balancing the backoffice (#20717)

* make file upload location configurable

* Update src/Umbraco.Core/Configuration/Models/HostingSettings.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Fix default implementation

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

src/Umbraco.Core/Configuration/Models/HostingSettings.cs

@@ -25,6 +25,12 @@ public class HostingSettings
     [DefaultValue(StaticLocalTempStorageLocation)]
     public LocalTempStorage LocalTempStorageLocation { get; set; } = Enum.Parse<LocalTempStorage>(StaticLocalTempStorageLocation);
 
+    /// <summary>
+    /// Gets or sets a value for the location of temporary file uploads.
+    /// </summary>
+    /// <value>/umbraco/Data/TEMP/TemporaryFile if nothing is specified.</value>
+    public string? TemporaryFileUploadLocation { get; set; }
+
     /// <summary>
     ///     Gets or sets a value indicating whether umbraco is running in [debug mode].
     /// </summary>

src/Umbraco.Core/Hosting/IHostingEnvironment.cs

@@ -43,7 +43,12 @@ public interface IHostingEnvironment
     string LocalTempPath { get; }
 
     /// <summary>
-    ///     The web application's hosted path
+    /// Gets the location of temporary file uploads.
+    /// </summary>
+    public string TemporaryFileUploadPath => Path.Combine(LocalTempPath, "TemporaryFile");
+
+    /// <summary>
+    ///     The web application's hosted path.
     /// </summary>
     /// <remarks>
     ///     In most cases this will return "/" but if the site is hosted in a virtual directory then this will return the