Add DescriptorSetLayoutCreateInfo and PipelineLayoutCreateInfo

[Rua]

Changelog:

- **Breaking** `DescriptorSetLayout` creation parameters are given using `DescriptorSetLayoutCreateInfo`. The getter methods on `DescriptorSetLayout` have been changed to match.
- **Breaking** `DescriptorDesc` has been renamed to `DescriptorSetLayoutBinding` and must now be constructed with struct update syntax. The `ty` member has been renamed to `descriptor_type`, and `variable_count` has been renamed to `variable_descriptor_count`.
- **Breaking** `PipelineLayout` creation parameters are given using `PipelineLayoutCreateInfo`. The getter methods on `PipelineLayout` have been changed to match.
- **Breaking** `PipelineLayoutPcRange` has been renamed to `PushConstantRange`.

More CreateInfofication. This one is relatively small in scope.

[AustinJ235]

Looks good!