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/Interrupts/SpuriousInterruptHandler.h

@@ -42,7 +42,7 @@ private:
     explicit SpuriousInterruptHandler(u8 interrupt_number);
     bool m_enabled { false };
     bool m_real_irq { false };
-    RefPtr<IRQController> m_responsible_irq_controller;
+    LockRefPtr<IRQController> m_responsible_irq_controller;
     OwnPtr<GenericInterruptHandler> m_real_handler;
 };
 }