feat: mrf crypto

[justynoh]

Problem

We want to implement multi-respondent forms. This PR implements the crypto primitives required to encrypt and decrypt multi-respondent form responses.

Solution

A new Crypto class, CryptoV3 is written to support the new encryption scheme. Common functions between Crypto and CryptoV3 are split into a CryptoBase parent class, which Crypto and CryptoV3 now inherit.

Breaking Changes

• No - this PR is backwards compatible

[gitguardian]

⚠️ GitGuardian has uncovered 2 secrets following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secrets in your pull request

GitGuardian id	Secret	Commit	Filename
9014825	Generic High Entropy Secret	ecd7b58	spec/resources/crypto-v3-data-20231207.ts	View secret
9014826	Generic High Entropy Secret	ecd7b58	spec/resources/crypto-v3-data-20231207.ts	View secret

🛠 Guidelines to remediate hardcoded secrets

1. Understand the implications of revoking this secret by investigating where it is used in your code.
2. Replace and store your secrets safely. Learn here the best practices.
3. Revoke and rotate these secrets.
4. If possible, rewrite git history. Rewriting git history is not a trivial act. You might completely break other contributing developers' workflow and you risk accidentally deleting legitimate data.

To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

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