Add new sample for VK_EXT_descriptor_heap

[SaschaWillems]

Description

This PR adds a new sample for the recently released VK_EXT_descriptor_heap extension. It shows off different heap types (resources, samplers). It only does the descriptor set and binding mapping way of using heaps. Untyped pointers might follow at a later point of certain things have been resolved (see our internal discussions).

Also comes with documentation/tutorial material.

Tested on Win11 with an Nvidia RTX 4070.

Fixes #1486

General Checklist:

Please ensure the following points are checked:

• My code follows the coding style
• I have reviewed file licenses
• I have commented any added functions (in line with Doxygen)
• I have commented any code that could be hard to understand
• My changes do not add any new compiler warnings
• My changes do not add any new validation layer errors or warnings
• I have used existing framework/helper functions where possible
• My changes do not add any regressions
• I have tested every sample to ensure everything runs correctly
• This PR describes the scope and expected impact of the changes I am making

Note: The Samples CI runs a number of checks including:

• I have updated the header Copyright to reflect the current year (CI build will fail if Copyright is out of date)
• My changes build on Windows, Linux, macOS and Android. Otherwise I have documented any exceptions

If this PR contains framework changes:

• I did a full batch run using the batch command line argument to make sure all samples still work properly

Sample Checklist

If your PR contains a new or modified sample, these further checks must be carried out in addition to the General Checklist:

• I have tested the sample on at least one compliant Vulkan implementation
• If the sample is vendor-specific, I have tagged it appropriately
• I have stated on what implementation the sample has been tested so that others can test on different implementations and platforms
• Any dependent assets have been merged and published in downstream modules
• For new samples, I have added a paragraph with a summary to the appropriate chapter in the readme of the folder that the sample belongs to e.g. api samples readme
• For new samples, I have added a tutorial README.md file to guide users through what they need to know to implement code using this feature. For example, see conditional_rendering
• For new samples, I have added a link to the Antora navigation so that the sample will be listed at the Vulkan documentation site

[SaschaWillems]

Please read:

• https://docs.vulkan.org/features/latest/features/proposals/VK_EXT_descriptor_heap.html
• https://docs.vulkan.org/guide/latest/descriptor_heap.html
• https://www.khronos.org/blog/vulkan-introduces-roadmap-2026-and-new-descriptor-heap-extension

There is nothing misleading about this example.

This PR is also a DRAFT.

[SaschaWillems]

This PR is now ready to review. I also added documentation/tutorial.

A variation using untyped pointers will follow independently at a later pointer.

[asuessenbach]

Looks great!

Just a couple of mostly minor issues:

[asuessenbach]

I think, we should not use const_cast in our samples. It's dangerous and not a good coding style.

But if nobody else complains, I'm ok with it.