refactor!: refactored transcript traits and impls

[alxiong]

As observed in https://www.notion.so/espressosys/Fiat-Shamir-Transcript-f29ccc7a23c94178aac5cfa5d336fd63 and discussed on Zulip, we decide to remove get_and_append_challenge() and only use get_challenge() and also introduce back state for solidity transcript as most other projects do.

This partially undone some changes made in https://github.com/EspressoSystems/jellyfish/pull/619.

This PR:

• Updated trait Transcript
  • change get_and_append_challenge() to get_challenge()
  • add get_n_challenges() for multiple challenges for the same rounds
  • rename append_challenge() to append_field()
  • add append_fields()
• Updated struct SolidityTranscript: adding back state and squeeze logic (see code comment)

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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 write a little note why.

• [x] ~Targeted PR against correct branch (main)~
• [x] ~Linked to GitHub issue with discussion and accepted design OR have an explanation in the PR that describes this work.~
• [x] ~Wrote unit tests~
• [x] Updated relevant documentation in the code
• [ ] Added relevant changelog entries to the CHANGELOG.md of touched crates.
• [ ] Re-reviewed Files changed in the GitHub PR explorer

[alxiong]

All of your comments are addressed in 2956aa5

I'll update the CHANGELOG when we merge all changes into main eventually.