Abort startup if config directory could not be found

We do not require any config files, but config directory - yes, we won't bother creating it manually as it heavily suggests user mistake, such as --path to the wrong directory.

ArchiSteamFarm/Localization/Strings.Designer.cs

@@ -845,6 +845,15 @@ namespace ArchiSteamFarm.Localization {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Config directory could not be found, aborting!.
+        /// </summary>
+        public static string ErrorConfigDirectoryNotFound {
+            get {
+                return ResourceManager.GetString("ErrorConfigDirectoryNotFound", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Configured {0} property is invalid: {1}.
         /// </summary>