Defines common roles across all offering types.
bytes32 public constant ISSUER_ROLE = keccak256("ISSUER_ROLE");
bytes32 public constant ATTESTOR_ROLE = keccak256("ATTESTOR_ROLE");
bytes32 public constant PLACEMENT_AGENT_ROLE = keccak256("PLACEMENT_AGENT_ROLE");
bytes32 public constant TRANSFER_AGENT_ROLE = keccak256("TRANSFER_AGENT_ROLE");
bytes32 public constant ACCREDITATION_AGENT_ROLE = keccak256("ACCREDITATION_AGENT_ROLE");