feat: add remaining constraints in aggchain proof

[hadjiszs]

Description

• Add verification of the l1 head
• Hardcode the hash of the aggregation vkey directly in the aggchain proof program
• Adapt for the optimisticMode
  • Align the aggchain_params expression
  • Add the case signature verification of the fep public values

Spin off in another PR (#89)

• Compute the hash chain global index from the prover inputs
• Add the "delete" hashChains
• Put the right static calls to retrieve the new and prev hash chain global index

PR Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added or updated tests that comprehensively prove my change is effective or that my feature works