Kernel: Make self-contained locking smart pointers their own classes

Until now, our kernel has reimplemented a number of AK classes to
provide automatic internal locking:

- RefPtr
- NonnullRefPtr
- WeakPtr
- Weakable

This patch renames the Kernel classes so that they can coexist with
the original AK classes:

- RefPtr => LockRefPtr
- NonnullRefPtr => NonnullLockRefPtr
- WeakPtr => LockWeakPtr
- Weakable => LockWeakable

The goal here is to eventually get rid of the Lock* classes in favor of
using external locking.

Kernel/Graphics/Console/VGATextModeConsole.h

@@ -13,7 +13,7 @@
 namespace Kernel::Graphics {
 class VGATextModeConsole final : public Console {
 public:
-    static NonnullRefPtr<VGATextModeConsole> initialize();
+    static NonnullLockRefPtr<VGATextModeConsole> initialize();
     virtual size_t chars_per_line() const override { return width(); };
 
     virtual bool has_hardware_cursor() const override { return true; }