WindowServer+LibGUI: Shrink window edge resize hot-spots

The hot-spots for resizing a window by dragging its corner are now
limited to a small area around the actual corner instead of an area with
1/3rd the length or width of the window.

The hot-spots to resize a window while holding a modifier key and the
right mouse button are unchanged.

Userland/Services/WindowServer/ResizeDirection.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2022, Mart G <martg_@hotmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+namespace WindowServer {
+
+enum class ResizeDirection {
+    None,
+    Left,
+    UpLeft,
+    Up,
+    UpRight,
+    Right,
+    DownRight,
+    Down,
+    DownLeft,
+    __Count
+};
+
+}