Use dynamic viewport states.

[crud89]

In Vulkan there are two ways for updating a viewport. Currently only static viewports, that are directly passed to the pipeline during creation are supported. The problem is, that a resize requires all pipelines to be recreated in this case, which can be inefficient. Dynamic viewport states do not require the pipeline itself to be recreated, but only the swap-chain. In this case, a vkCmdSetViewport call is made to set the viewport. The problem with this approach, however, is, that it might not be as efficient during runtime.

Since there are tradeoffs with both approaches, we should support them both.

[crud89]

There is an overhead with re-creating all pipelines when resizing the frame buffer. The only reason why pipelines are re-created is to support viewport and scissor resizing. Meanwhile, dynamic viewport an scissor states do not have any significant impact on render performance (only one vkCmdSetViewport and one vkCmdSetScissor call per pipeline bind event). Hence we could drop static viewports alltogether in favor of more straightforward resize handling.