Background jobs and callbacks

[psiberx]

• Added support for callbacks

  auto loader = RED4ext::ResourceLoader::Get();
  auto token = loader->LoadAsync(R"(base\vehicles\sport\v_sport1_herrera_outlaw_basic_01.ent)");
  token->OnLoaded([](RED4ext::Handle<RED4ext::CResource>& aResource) {
  Log("Resource is loaded");
  });

  auto rtti = RED4ext::CRTTISystem::Get();
  rtti->AddRegisterCallback([&rtti] {
  Log("RTTI Type Registration");
  });

• Added support for background jobs

  auto loader = RED4ext::ResourceLoader::Get();
  auto token = loader->LoadAsync(R"(base\vehicles\sport\v_sport1_herrera_outlaw_basic_01.ent)");
  {
  RED4ext::JobQueue queue; // Jobs in one queue are sequential
  queue.Dispatch([]{ Log("Job A-1"); });
  queue.Dispatch([]{ Log("Job A-2"); });
  queue.Dispatch([]{ Log("Job A-3"); });
  Log("Checkpoint A");
  }
  {
  RED4ext::JobQueue queue;
  queue.Dispatch([]{ Log("Job B-1"); });
  queue.Wait(token->job); // Suspends jobs in the queue
  queue.Dispatch([]{ Log("Job B-2"); });
  queue.Dispatch([]{ Log("Job B-3"); });
  Log("Checkpoint B");
  }

  [0.420] Checkpoint A
  [0.420] Job A-1
  [0.420] Job B-1 <-- job can start immediately, even before checkpoint B
  [0.420] Checkpoint B
  [0.420] Job A-2
  [0.420] Job A-3 <-- all previous jobs executed at the same timestamp
  [0.462] Job B-2 <-- continues when the resource is ready
  [0.462] Job B-3

• Refactored memory utils and resource references

[WopsS]

Let me know if it is ready to be merged.

[psiberx]

Ready.