Add options for subpass and multisampling

[anas2660]

Adds options for subpass and multisampling when creating the graphics pipeline. Say that you have a renderpass with a single subpass that is multisampled (4x) and resolved directly to the surface image. For this case you could set the option multisampling to vk::SampleCountFlags::TYPE_4, and it would render correctly.

However, if you have 2 subpasses, for example:

• 3D render (4x multisampling) ---resolve--> 2D UI render (no multisampling) You maybe want to render to the second subpass. For this case you could set the option subpass to 1.

[adrien-ben]

Thank you! Looks good to me.

[adrien-ben]

version 1.15.0 is available with your modifications, thanks again