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/FileSystem/SysFS/Subsystems/Bus/PCI/BusDirectory.cpp

@@ -16,7 +16,7 @@ namespace Kernel {
 
 UNMAP_AFTER_INIT void PCIBusSysFSDirectory::initialize()
 {
-    auto pci_directory = adopt_ref(*new (nothrow) PCIBusSysFSDirectory());
+    auto pci_directory = adopt_lock_ref(*new (nothrow) PCIBusSysFSDirectory());
     SysFSComponentRegistry::the().register_new_bus_directory(pci_directory);
 }