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/Intel/NativeGraphicsAdapter.h

@@ -20,7 +20,7 @@ class IntelNativeGraphicsAdapter final
     , public PCI::Device {
 
 public:
-    static RefPtr<IntelNativeGraphicsAdapter> initialize(PCI::DeviceIdentifier const&);
+    static LockRefPtr<IntelNativeGraphicsAdapter> initialize(PCI::DeviceIdentifier const&);
 
     virtual ~IntelNativeGraphicsAdapter() = default;
 
@@ -29,6 +29,6 @@ private:
 
     explicit IntelNativeGraphicsAdapter(PCI::Address);
 
-    RefPtr<IntelNativeDisplayConnector> m_display_connector;
+    LockRefPtr<IntelNativeDisplayConnector> m_display_connector;
 };
 }