Feat: add support for tokenization

[redaLaanait]

• Add a Token Engine low-level component with two implementations (dynamodb and in-memory)
• Refactor Dynamodb Engine to implement both Token and Key engine interfaces.
• Update Protector service to support tokenization.
• Add and expose pii.Redact and pii.Check helper functions
• Change dynamodb partition keys design to fix tokens & keys conflict (breaking change).
• Refactor wire format; add the subjectID to allow PII field decryption independently from the struct.