[RFE] Utilize "enhanced barriers", reach parity with VK

[dzhdanNV]

https://microsoft.github.io/DirectX-Specs/d3d/D3D12EnhancedBarriers.html

It should help to make D3D12 backend closer to VK (with legacy resource states there are some hidden discrepancies). According to the spec "resource transitions" are emulated using "enhanced barriers" API under the hood.

[dzhdanNV]

API changes: this API instead of old one:

NRI_STRUCT(AccessDependency)
{
    NRI_NAME(AccessBits) acessBits;
    NRI_NAME(Dependency) dependency;
};

NRI_STRUCT(AccessDependencyLayout)
{
    NRI_NAME(AccessBits) acessBits;
    NRI_NAME(Dependency) dependency;
    NRI_NAME(TextureLayout) layout;
};

NRI_STRUCT(GlobalBarrierDesc)
{
    NRI_NAME(AccessDependency) before;
    NRI_NAME(AccessDependency) after;
};

NRI_STRUCT(BufferBarrierDesc)
{
    NRI_NAME(Buffer)* buffer;
    NRI_NAME(AccessDependency) before;
    NRI_NAME(AccessDependency) after;
};

NRI_STRUCT(TextureBarrierDesc)
{
    NRI_NAME(Texture)* texture;
    NRI_NAME(AccessDependencyLayout) before;
    NRI_NAME(AccessDependencyLayout) after;
    NRI_NAME(Mip_t) mipOffset;
    NRI_NAME(Mip_t) mipNum;
    NRI_NAME(Dim_t) arrayOffset;
    NRI_NAME(Dim_t) arraySize;
};

NRI_STRUCT(BarrierGroupDesc)
{
    const NRI_NAME(GlobalBarrierDesc)* globalBarriers;
    const NRI_NAME(BufferBarrierDesc)* bufferBarriers;
    const NRI_NAME(TextureBarrierDesc)* textureBarriers;
    uint32_t globalBarrierNum;
    uint32_t bufferBarrierNum;
    uint32_t textureBarrierNum;
};

// Barrier (can be used inside "Graphics" but with limited functionality)
void (NRI_CALL *CmdBarrier)(NRI_NAME_REF(CommandBuffer) commandBuffer, const NRI_NAME(BarrierGroupDesc)* barrierGroup);

[dzhdanNV]

If Agility SDK is not enabled, "legacy barriers" will be used to implement this API in D3D12, but:

• Dependency will be ignored
• aliasing barriers will become unsupported, because "legacy barriers" require resource "before" and "after"

[dzhdanNV]

Implemented.