Update base URL retrieval to use configuration setting

Replaced hardcoded base URL construction with a configuration-based approach for better management and flexibility. Updated `appsettings.json` to include the new `BaseUrl` setting under the `Hosting` section.

src/apps/Elsa.ServerAndStudio.Web/Pages/_Host.cshtml

@@ -2,7 +2,7 @@
 @addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
 @inject IConfiguration Configuration;
 @{
-    var baseUrl = $"{Request.Scheme}://{Request.Host}";
+    var baseUrl = Configuration["Hosting:BaseUrl"]!;
     var apiUrl = baseUrl + Url.Content("~/elsa/api");
     var basePath = Configuration["Hosting:BasePath"]!;
 }

src/apps/Elsa.ServerAndStudio.Web/appsettings.json

@@ -18,6 +18,7 @@
     "MySql": "Server=localhost;Database=elsa;Uid=user;Pwd=password;"
   },
   "Hosting": {
+    "BaseUrl": "https://localhost:5001",
     "BasePath": ""
   },
   "Identity": {