feat: ConfidentialERC20Wrapped/ConfidentialWETH

[PacificYield]

This PR adds two Solidity contracts: ConfidentialERC20Wrapped.sol and ConfidentialWETH.sol.

It breaks the coverage and needs a fix to avoid doing so.It breaks because of the use of hardhat_setBalance

[jatZama]

burn logic seems good, however there is one main issue as discussed on Slack:
For the WrappedETH currently if callback of the unwarp fails in case callSucess is false, it will make the user locked and lose his funds forever.
Current agreed solution is to handle this case differently: if callSuccess is false, instead of reverting the callback, the burn should not happen, but the user should still get unlocked, this was he has an opportunity to transfer his funds to an EOA for instance and then still being able to recover his funds by making a new request.
For the ERC20 Wrapper, there is a very similar issue, so we should add a try catch around the safeTransferFrom for instance.

[jatZama]

Also not to forget: remove the duplicate fallback, the receive function is sufficient in the Wrapped ETH.

[jatZama]

Also maybe for increased security, it could make sense to allow the user to call an unlockAfterMaxDedline function in case the Gateway was never able to send back a decryption request on time. But since the Gateway design is being reworked now, we could do this in a future version, just something to keep in mind here.