feat: Kakarot messaging system

[enitrat]

Feature Request

Describe the Feature Request

Implement Kakarot's messaging system

• L1 -> L2 Messaging
• L2 -> L1 Messaging

Describe Preferred Solution

Related Code

Additional Context

As a precompile at address 75002.

For Kakarot Precompiles (calling Cairo contract), the whitelist on who can call a precompile is based on the address of the code that calls this precompile. https://github.com/kkrt-labs/kakarot/blob/f1e7ebb9599a563aec9ffabbf11739373de8587c/src/kakarot/interpreter.cairo#L71-L77 https://github.com/kkrt-labs/kakarot/blob/f1e7ebb9599a563aec9ffabbf11739373de8587c/src/kakarot/precompiles/precompiles.cairo#L138

References:

https://github.com/kkrt-labs/kakarot/blob/65e333a0d3475e81b0a6367b0f00561c763da0a0/src/kakarot/precompiles/kakarot_precompiles.cairo#L126-L172

https://github.com/kkrt-labs/kakarot/blob/65e333a0d3475e81b0a6367b0f00561c763da0a0/src/kakarot/kakarot.cairo#L338-L354