Layer composition rendering using RenderPass, optimization

[mvaligursky]

related to issue: #4271
follow up on PR: #4272
partially implements #2396

new (private) APIs:

GraphicsDevice.startPass(renderPass);
GraphicsDevice.endPass(renderPass);

This PR further implements the FrameGraph / RenderPass rendering architecture, specifically:

• the frame graph tracks load and store operations for render targets, in order to avoid some wasted loading and storing those to tiled memory
• the frame graph optimizes resolve and generate mipmaps operations as well

The benefits are mostly visible in projects that render to textures, especially if multi-sampling is used, including rendering to cubemaps.

GPU Performance improvement on some engine examples:

Other changes

• log tracing added for render passes:
  

• log tracing added for texture / render target allocation / deallocation
  

[slimbuck]

To infinity and beyond!

[slimbuck]

Suggested change

	const realPass = this.renderTarget !== undefined;
	const realPass = this.renderTarget !== null;

[mvaligursky]

same as above. null is a valid 'render target' (a default framebuffer), which is not the same as undefined, which represents no render target.

[slimbuck]

Still wondering ab this one?

[willeastcott]

Approving based on a layout + spelling + grammar pass. 😄 I'll leave a technical approval to @slimbuck.