feat: first working fhevm-native implementation

[david-zk]

Trivial encryption and adding numbers are working, all operands not thoroughly tested yet

Some changes to the api:

• Commit function now should be called at the end of every block, it will do two things: 1) insert ciphertexts to the evm storage queue 2) flush pending ciphertexts from the cache to the evm storage

Still to be done:

• track SSTORE opcode to see which ciphertexts are allowed to be persisted inside the cache
• implement API call on blockchain first startup to load relevant ciphertexts from evm storage to the ciphertext cache (using evm ciphertext queue to know which ones are to be computed next)
• add magic number to know whether we're reading ciphertext from the storage
• support ciphertext input transactions

@antoniupop @dartdart26