[docs] Inference section cleanup

[stevhliu]

Removes some duplicate entries in the toctree. Also moves the Controlling image quality guide to the Community optimizations section as it is entirely focused on FreeU.

[HuggingFaceDocBuilderDev]

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[sayakpaul]

I think we can slowly remove these from our documentation as this has grown quite old.

[stevhliu]

Sounds good to me! I can add a label at the top warning that it will be deprecated in the near future. Which of these community optimizations should we remove? FreeU, T-GATE, ToME, and maybe DeepCache?

[sayakpaul]

I think ToME, DeepCache, etc. are still relevant in the sense that they help accelerate speed. But I guess we don't have to cater to the deprecation notice immediately.