Remove encryptMessageWithPrivateKey and decryptMessageWithPrivateKey from cryptography

[ishantiw]

Description

• Remove encryptMessageWithPrivateKey and decryptMessageWithPrivateKey methods from lisk-cryptography
• With the above change we can also remove edcurve2 library and box/openBox from nacl usage in lisk-cryptography
• Update encrypt/decrypt commands in lisk-commander to use encryptMessageWithPassword/decryptMessageWithPassword

Acceptance Criteria

• Mentioned methods and libraries should be removed
• encrypt/decrypt command should work and also pass the unit tests in Lisk Commander