Use Ash builders for Vulkan struct construction + refactor

[Rua]

The Ash builder methods are now used instead of raw pointers, so that lifetimes are correctly tracked. This did, however, need some significant refactoring because of how borrowing rules work. For that reason, I moved all Ash struct construction into the structs themselves (as methods). The methods and structs follow a tiered logic where each value borrows from those below it:

• to_vk -> ash::vk::FooCreateInfo
• to_vk_extensions -> mut FooCreateInfoExtensionsVk
• to_vk_fields1 -> FooCreateInfoFields1Vk
• to_vk_fields1_extensions -> mut FooCreateInfoFields1ExtensionsVk
• to_vk_fields2 -> FooCreateInfoFields2Vk
• to_vk_fields2_extensions -> mut FooCreateInfoFields2ExtensionsVk
• to_vk_fields3 -> FooCreateInfoFields3Vk
• etc.

Mutable borrows are needed for the extension structs because push_next takes a mutable reference.

The DeviceFeatures and DeviceProperties construction have been left out of this, those need more attention that will be done in a separate PR.