ImGUI Improvements

[deprilula28]

Description

From the commit in https://github.com/Devsh-Graphics-Programming/Nabla/pull/344

• [ ] Bindless textures
• [ ] Programmable scissors using clip planes
• [ ] Single draw call render
• [ ] Keyboard inputs
• [ ] Create IGPUImage straight away and copy buffer to image for image upload on the UI example

[devshgraphicsprogramming]

a workaround will be needed for the textures, maybe an accessor-pattern to hide the impl and desc set used.

https://github.com/microsoft/DirectXShaderCompiler/issues/6498 https://github.com/microsoft/DirectXShaderCompiler/issues/5092