Kernel: Rename Kernel/VM/ to Kernel/Memory/

This directory isn't just about virtual memory, it's about all kinds
of memory management.

Kernel/Memory/ProcessPagingScope.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+#include <Kernel/Forward.h>
+
+namespace Kernel {
+
+class ProcessPagingScope {
+public:
+    explicit ProcessPagingScope(Process&);
+    ~ProcessPagingScope();
+
+private:
+    u32 m_previous_cr3 { 0 };
+};
+
+}