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/Firmware/Directory.cpp

@@ -15,7 +15,7 @@ namespace Kernel {
 
 UNMAP_AFTER_INIT void FirmwareSysFSDirectory::initialize()
 {
-    auto firmware_directory = adopt_ref_if_nonnull(new (nothrow) FirmwareSysFSDirectory()).release_nonnull();
+    auto firmware_directory = adopt_lock_ref_if_nonnull(new (nothrow) FirmwareSysFSDirectory()).release_nonnull();
     SysFSComponentRegistry::the().register_new_component(firmware_directory);
     firmware_directory->create_components();
 }