WebGL: sRGB swapchain

[MikhailGorobets]

Currently, we are facing issues with tutorials when running them in the browser on the WebGL backend due to the absence of conversion to the sRGB space. It might be better to emulate sRGB directly in the SwapChain if the user creates it with an sRGB format. To achieve this, we could add a FullQuad pass during the Present call, where the corresponding transformation would be performed

[TheMostDiligent]

This will require extra full-screen pass, which may not be desirable, especially on high-resolution displays.

[MikhailGorobets]

This should be inexpensive compared to our post-processing passes