Unify vkb::Subpass and vkb::rendering::HPPSubpass into vkb::rendering::Subpass<bindingType>

[asuessenbach]

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Build tested on Win10 with VS2022. Run tested on Win10 with NVidia GPU.

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[SaschaWillems]

This does work fine for me (tested a few samples with the batch run), but I',m kinda unsure about the actual interface.

Once we have unified the repo will we have to add the binding type to each and every class from the framework? If so, I fear that this will make the code hard to read.

e.g. comparing this:

std::vector<std::unique_ptr<vkb::Subpass>> subpasses{};

with:

std::vector<std::unique_ptr<vkb::rendering::Subpass<vkb::BindingType::C>>> subpasses{};

Imo readability suffers a lot. Is it possible to somehow omit the binding type unless one explicitly wants to use the CPP variants?

[asuessenbach]

I agree, the resulting types are somewhat longer than before.

• I moved the class Subpass from namespace vkb to vkb::rendering, to make it clear where it resides. If it's consensus that that is a bad move, it would be easy to revert that.
• In order to have the very same class work for both, the C- and the C++-bindings, that BindingType template parameter is added. It is needed. One could, though, add some type aliases like

using SubpassC   = Subpass<vkb::BindingType::C>;
using SubpassCpp = Subpass<vkb::BindingType::Cpp>;

which would reduce the aforementioned complexity a bit:
std::vector<std::unique_ptr<vkb::rendering::SubpassC>> subpasses{};
If it's consensus, I could easily add something like that.