Add install target and integration tests

[aqnuep]

This solution is far from perfect, as the project lacks a proper directory structure, but at least allows for using the repository as a dependency in ecosystem components.

If preferred, we can rework the directory structure too.

[aqnuep]

I spoke too soon, I just realized that this code depends on the vulkan_sc_core.hpp, i.e. the C++ header, which is quite unfortunate, because it makes it incompatible with the ecosystem components in general, which do not generate combined C++ headers of any sort.

[dgkoch]

I spoke too soon, I just realized that this code depends on the vulkan_sc_core.hpp, i.e. the C++ header, which is quite unfortunate, because it makes it incompatible with the ecosystem components in general, which do not generate combined C++ headers of any sort.

Does it really though? All it really needs is what's defined in fake/vulkan/vulkan_sc_core.hpp which is just the pipeline cache structures, which should be the same as those in the C header.

[aqnuep]

I guess where I'm trying to get to is that probably we should do some more intrusive changes and put together something more robust, one of them being the chamge to the used includes, but sure, you're right.

[dgkoch]

I don't mind if you want to do it more robustly. I made the fake header thing long before we had the VulkanSC-Headers repo that we could pull in easily.

[aqnuep]

Closing this MR for now, we will figure out the long-term plan for this first.