feat(rust/catalyst-voting): Parallel iter usage for fn encrypt_vote

[Mr-Leshiy]

Description

• Added rayon lib
• Updated encrypt_vote function with the parallel iterator usage.

Performance measurements on Apple M1
Old version:

vote protocol benchmark/vote encryption
                        time:   [243.70 µs 243.88 µs 244.14 µs]

New version:

vote protocol benchmark/vote encryption
                        time:   [139.87 µs 141.72 µs 144.27 µs]
                        change: [-42.351% -41.334% -40.375%] (p = 0.00 < 0.05)
                        Performance has improved.

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 211/211}$ | ${\color{red}Fail: 0/211}$ |

[minikin]

lgtm