canister replay attack prevention measures

[akashkumar1691]

• [x] create in-canister authed gate way
• [x] write all functions in gateway
• [x] write check timestamp function
• [x] add result return values to db and acl functions
• [x] add error checking and rejection messages to methods.rs
• [x] check timestamp in gateway
• [x] call underlying function
• [x] update candid
• [x] update agent
  • [x] add timestamp args
  • [x] update error checking
• [ ] test