feat: Implement D3D12 resource factory and improve swap chain management

- Added D3D12ResourceFactory for creating render targets, textures, and buffers.
- Enhanced D3D12SwapChain to manage back buffer render targets and provide access to them.
- Updated D3D12Texture to utilize resource handles for better resource management.
- Removed legacy ResourceAllocator and integrated improvements for resource handling.
- Introduced new interfaces for resource factory and swap chain to streamline resource creation.
- Added support for mip levels and texture dimensions in render target and texture descriptions.
- Created new markdown files to document allocator and swap chain improvements.

Ghost.Graphics/RHI/ISwapChain.cs

@@ -28,6 +28,12 @@ public interface ISwapChain : IDisposable
     /// <returns>Current back buffer texture</returns>
     ITexture GetCurrentBackBuffer();
 
+    /// <summary>
+    /// Gets the current back buffer as a render target
+    /// </summary>
+    /// <returns>Current back buffer render target</returns>
+    IRenderTarget GetCurrentBackBufferRenderTarget();
+
     /// <summary>
     /// Presents the rendered frame
     /// </summary>