[Update]: Fuzz test using the Echidna

[Mohsen-T]

• Used echidna.yaml for the configuration of Echidna.
• Developed a script named .echidna.test.js for wrapping parameters like contract name, path, etc.
• Developed Operators.sol for fuzz testing of SSVOperators.sol, Clusters.sol for SSVClusters.sol, and DAO.sol for SSVDAO.sol.
• Found some issues from the fuzz testing; I would like to discuss them in the presentation.
• Used the assertion mode for fuzz testing, among options such as property, assertion, dapptest, etc.