Enable delegates to sign on behalf of user

[peersky]

If we implement ERC4337 workflow and support smart accounts, the user account participating in the games will not be able to sign off their transactions eventually.

We need to add mapping for participant qualified delegates who are performing as session keys on healf of user in form of mapping(address user => address delegate) delegates;

Due to fact that it is likely that delegates will be managed per user perhaps for multiple possible subjects, this mapping shall be not property of an instance but rather a global protocol value of peeramid network which instances treat as source of trust