Fixing some trait bound

[alxiong]

Description

Major changes include:

• A missing modification for no_std compliance and refactor SNARK trait #87 in 6ee2ac0
• Remove unnecessary Clone on some trait bound: P: Parameters + Clone -> P: Parameters, whose source is our trait Gate, and trick I use is by relying on object-safe dyn_clone

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• Targeted PR against correct branch (main)
• Linked to GitHub issue with discussion and accepted design OR have an explanation in the PR that describes this work.
• Wrote unit tests
• Updated relevant documentation in the code
• Added a relevant changelog entry to the Pending section in CHANGELOG.md (@zhenfeizhang I don't think we need to add this to changelog, WDYT?)
• Re-reviewed Files changed in the GitHub PR explorer

[zhenfeizhang]

In general LGTM. A question: why do we need CloneGate in the first place? Is it possible to simply remove impl<F: Field> Clone for Box<dyn Gate<F>>?

[mrain]

LGTM.

[alxiong]

why do we need CloneGate in the first place? Is it possible to simply remove impl<F: Field> Clone for Box<dyn Gate>?

because of this. I was using the suggested answer there, until I saw the better option below (i.e dyn_clone crate)

[zhenfeizhang]

why do we need CloneGate in the first place? Is it possible to simply remove impl<F: Field> Clone for Box?

because of this. I was using the suggested answer there, until I saw the better option below (i.e dyn_clone crate)

Thanks!