Apply key formatting to encrypt command

[oliviathet]

Summary & Motivation (Problem vs. Solution)

Add --key-format flag for encrypt command that accepts mnemonic (default), hexadecimal, and solana.

turnkey encrypt \
--import-bundle-input "./import_bundle.txt" \
--encrypted-bundle-output "./encrypted_bundle.txt" \
--plaintext-input /dev/fd/3 3<<<"$SEEDPHRASE_1"
--key-format "mnemonic"

Tested the following scenarios:

• encrypt mnemonic with no --key-format flag then import wallet ✅
• encrypt mnemonic with --key-format mnemonic flag then import wallet ✅
• encrypt hex-encoded hex key with --key-format hexadecimal flag then import key w ethereum address format and secp256k1 curve ✅
• encrypt phantom solana key with --key-format solana flag then import key w solana address format and ed25519 curve ✅

Release Steps

See README for additional details.

• Tag the release (once approved)
• Attest (once merged)
• Create release with changelog
• Update Homebrew tap