Add ERC-2494 compliant BabyJubJub

[vasemkin]

Description

This PR builds upon the work by @Shigoto-dev19 in the archived arkworks-rs/curves repository. Please see the relevant discussions.

• Added a Circom compatible Baby Jubjub elliptic curve according to ERC-2494
  • The literature test cases are verified(not explicitly added in order to respect the architecture!).
  • The architecture is kept the same as the other Twisted Edwards curves by arkworks-rs/curves.

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Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
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• Targeted PR against correct branch (master)
• 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
• Re-reviewed Files changed in the GitHub PR explorer

[luksgrin]

What is the status on this PR? I'd love to switch to an arkworks implementation, currently using https://crates.io/crates/babyjubjub-rs (which is discouraged by its author).

[Pratyush]

@vasemkin thank you for the PR, and sorry for the delay here. Could you update the README in curves to include a link to the crate, and also to clarify the difference between ed_on_bn254 and ark-baby-jubjub? Also, could you add the literature tests you mentioned? Since these are just additional tests there is no issue.