Release candidate 2.0.0rc3

[Argmaster]

• Added changelog content.
• Fixed outdated README.md examples (Image from Rasterized2DLayer.render/Layer #34).
• Added get_image() method to Rasterized2DRenderingResult and Rasterized2DResultHandle objects.
• Added CI (Add Github Actions CI configs #39).
• Added issue templates (Update issue templates #38).

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This discussion was created from the release Release candidate 2.0.0rc3.