perf: optimize editor->IMGUI

[yyc-git]

TODO use ImGui.ShowMetricsWindow() to show debug

description
run the editor is slow

reason
now even run the simplest editor(Scene View + Game View), GPU will take 8ms in each frame. the imgui cost GPU

solution
1.reduce ui size
e.g. reduce window size which are overlay by upper ui controls

but this lead only a litter increase fps

2.optimize imgui
refer to:
Performance improvement suggestion
https://community.intel.com/t5/Intel-oneAPI-Data-Parallel-C/Optimizing-Performance-and-Memory-Usage-in-ImGui-based/td-p/1464228
Could ImGUI Be the Future of GUIs?

TODO optimize Scene/Game View?

3.imgui use webgpu backend

/*
4..use UIElements
refer to:
https://blog.csdn.net/u010019717/article/details/102540067
https://www.slideshare.net/unity3d/built-for-performance-the-uielements-renderer-unite-copenhagen-2019

*/