Implement Comet header verifier in Cairo

[Farhad-Shabani]

Context

Implement a Comet header verifier to validate untrusted headers based on a previously verified block. The logic should mirror the existing implementation in the tendermint-light-client-verifier crate (More specifically verify_update_header).
It might be more appropriate to house all header verification logic and related data structures in a dedicated Cairo library. This library could also include misbehavior checks, which will be accomplished as a separate issue.

The implementation should be thoroughly tested with unit tests.