vk_fence_manager: Use timeline semaphores instead of spin waits

With timeline semaphores we can avoid creating objects. Instead of
creating an event, grab the current tick from the scheduler and flush
the current command buffer. When the fence has to be queried/waited, we
can do so against the master semaphore instead of spinning on an event.

If Vulkan supported NVN like events or fences, we could signal from the
command buffer and wait for that without splitting things in two
separate command buffers.