feat(encryption) [1/N] Support encryption: Add crypto for AES-GCM (#2026)

Add Core Encryption Primitives for Iceberg Encryption Support.

Part of #2034

## Summary

This PR introduces the foundational cryptographic primitives needed for
implementing encryption in iceberg-rust, providing AES-GCM encryption
operations that match the Java implementation's behavior and data
format.

 ## Motivation

Iceberg's Java implementation supports table-level encryption to protect
sensitive data at rest. To achieve feature parity and ensure
interoperability between Java and Rust implementations, we need to build
encryption support from the ground up. This PR provides the core
cryptographic operations that will serve as the foundation for the
complete encryption feature.

 ## Changes

  New Module: encryption

Added a new encryption module with core AES-GCM cryptographic
operations:

  - encryption/crypto.rs - Core encryption implementation
- EncryptionAlgorithm enum supporting AES-128-GCM as this is the only
algorithm currently supported in arrow parquet
    - SecureKey struct with automatic memory zeroization for security
- AesGcmEncryptor providing encrypt/decrypt operations with AAD support

  Key Features

1. Java-Compatible Format: Ciphertext format matches Java's
implementation exactly:
  [12-byte nonce][encrypted data][16-byte GCM authentication tag]
1. This ensures files encrypted by Java can be decrypted by Rust and
vice versa.
2. Secure Key Handling: Uses the zeroize crate to automatically clear
encryption keys from memory when dropped, preventing key material from
lingering in memory.
3. Additional Authenticated Data (AAD): Full support for AAD to ensure
integrity of associated metadata that isn't encrypted.
  4. Comprehensive Testing: 8 tests covering:
    - Round-trip encryption/decryption for both AES-128 and AES-256
    - AAD validation
    - Empty plaintext handling
    - Tamper detection
    - Format compatibility verification

  Dependencies Added

  - aes-gcm = "0.10" - Industry-standard AES-GCM implementation
  - zeroize = "1.7" - Secure memory cleanup for encryption keys

  Compatibility

This implementation directly corresponds to Java's
https://github.com/apache/iceberg/blob/main/core/src/main/java/org/apache/iceberg/encryption/Ciphers.java:

| Java Class | Rust Implementation |

|-----------------------------|------------------------------------------|
| Ciphers.AesGcmEncryptor | AesGcmEncryptor::encrypt() |
| Ciphers.AesGcmDecryptor | AesGcmEncryptor::decrypt() |
  | EncryptionAlgorithm.AES_GCM | EncryptionAlgorithm::Aes128Gcm|

  Testing

  Future Work

This PR is the first in a series to implement full encryption support.
Upcoming PRs will add:

  1. Table properties for encryption configuration
  2. Key management interfaces (KeyManagementClient trait)
  3. EncryptionManager implementation
  4. Native Parquet encryption integration
  5. AWS KMS support
  6. Integration with Table and FileIO

  Review Notes

  - This PR is intentionally minimal and self-contained
  - No existing code paths are modified - this is purely additive
  - The module is public but won't be used until future PRs wire it up
- Format compatibility with Java has been prioritized to ensure
interoperability


## Which issue does this PR close?

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- Closes #. #2035

## What changes are included in this PR?

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## Are these changes tested?
Yes
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Author: xanderbailey