Cosmetics changes to the readme.

[AbdelStark]

Changes summary

• Add logo in the readme header
• Add a header section with badges (CI tests, coverage, license)
• Refactor readme, reframe, add elements
• Add benchmarks section with instructions on how to run benchmarks and find visual reports that are published by the CI
• Add contributors section and use all-contributors

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This change is 

[alonh5]

Reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @AbdelStark)

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README.md line 47 at r1 (raw file):

## 📊 Benchmarks

Benchmarks can be run using `cargo bench`.

We added a script to run a single-threaded poseidon2 hash proof benchmark, it's called poseidon_benchmark.sh (there''s a mistake in the current README). Could you please add that here as well?

[shaharsamocha7]

Merged from another branch