Kernel: New handle manager

This handle manager more closely mirrors the behaviour of the CTR-OS
one. In addition object ref-counts and support for DuplicateHandle have
been added.

Note that support for DuplicateHandle is still experimental, since parts
of the kernel still use Handles internally, which will likely cause
troubles if two different handles to the same object are used to e.g.
wait on a synchronization primitive.

src/core/hle/kernel/thread.cpp

@@ -341,7 +341,8 @@ Thread* CreateThread(Handle& handle, const char* name, u32 entry_point, s32 prio
 
     Thread* thread = new Thread;
 
-    handle = Kernel::g_handle_table.Create(thread);
+    // TOOD(yuriks): Fix error reporting
+    handle = Kernel::g_handle_table.Create(thread).ValueOr(INVALID_HANDLE);
 
     thread_queue.push_back(handle);
     thread_ready_queue.prepare(priority);