feat: added system page to manage background tasks and get basic system information

gaseous-tools/Common.cs

@@ -66,6 +66,24 @@ namespace gaseous_tools
 				}
 			}
 		}
-	}
+
+        public static long DirSize(DirectoryInfo d)
+        {
+            long size = 0;
+            // Add file sizes.
+            FileInfo[] fis = d.GetFiles();
+            foreach (FileInfo fi in fis)
+            {
+                size += fi.Length;
+            }
+            // Add subdirectory sizes.
+            DirectoryInfo[] dis = d.GetDirectories();
+            foreach (DirectoryInfo di in dis)
+            {
+                size += DirSize(di);
+            }
+            return size;
+        }
+    }
 }