feat: allow fee delegation only for smart accounts

[Agilulfo1820]

Currently everyone can use the delegator url created on vechain energy. We need to write a smart contract to check if the transaction is for the smart account. Something like this:

interface IPrototype {
     function master(address _self) returns (address);
}

// …
    function canSponsorTransactionFor(
        address _origin,
        address _to,
        bytes calldata _data
    ) public view returns (bool) {
       if (IPrototype(0x000000000000000000000050726f746F74797065).master(_to) == 0xDeployerAddress) {
           return true;
       }

       return false;
    }