Improved Keyboard/Gamepad Input & Widget Focus Handling for UMG Menus

[Ryan_Darcey]

I added this function to track widget focus in Ticks which is super gross/not optimized, but it makes for some WAY cleaner HUD blueprints.

UWidget* APFPlayerController::GetCurrentWidgetFocus()
{
    for (TObjectIterator<UWidget> Itr; Itr; ++Itr)
    {
        if (Itr->HasUserFocus(this))
            return *Itr;
    }

    return nullptr;
}