Implement Real Genesis Certificate

[jpraynaud]

This PR implements the Real Genesis Certificate:

• Add a Genesis Signer that signs a message with a Genesis Secret Key (only for test purpose)
• Add a Genesis Verifier that verifies a Genesis Signature against a Genesis Verification Key
• Implement the verify_genesis_certificate of the Certificate Verifier
• Make Client load/use the Genesis Verification Key
• Make Aggregator load/use the Genesis Verification Key
• Make Aggregator verify that the Certificate Chain is valid before trying to produce new Mithril Certificates
• Add a sub command to the Aggregator CLI to generate test only Genesis Keys, and boostrap a test only Genesis Certificate
• Add a sub command to the Aggregator CLI to export the message that must be signed with Genesis Secret Key into a Genesis Signature
• Add a sub command to the Aggregator CLI to import the Genesis Signature and create a Genesis Certificate
• Update test lab to bootstrap a Genesis Certificate
• Update devnet standalone to bootstrap a Genesis Certificate
• Update GCP Aggregator to use the test Genesis Keys
• Fix crashes of the end to end tests in CI
• Update documentations

Closes #364

[github-actions]

Unit Test Results

    7 files  ±  0    22 suites  ±0   2m 3s ⏱️ -24s
318 tests +24  318 ✔️ +24  0 💤 ±0  0 ❌ ±0 
319 runs  +24  319 ✔️ +24  0 💤 ±0  0 ❌ ±0 

Results for commit c0e1cff. ± Comparison against base commit 3f9a99a.

This pull request removes 7 and adds 31 tests. Note that renamed tests count towards both.

runtime::runner::tests ‑ test_certificate_exist_for_beacon
runtime::runner::tests ‑ test_is_new_beacon
runtime::state_machine::tests ‑ idle_certificate_already_exist_for_beacon
runtime::state_machine::tests ‑ idle_check_no_new_beacon_with_no_current_beacon
runtime::state_machine::tests ‑ signing_multisig_ready_to_idle
runtime::state_machine::tests ‑ signing_same_beacon_to_signing
runtime::state_machine::tests ‑ unregistered_no_transition

certificate_handler::tests ‑ test_epoch_settings_ko_500
certificate_handler::tests ‑ test_epoch_settings_ok_200
crypto_helper::genesis::tests ‑ test_codec_genesis_keypair
crypto_helper::genesis::tests ‑ test_generate_test_deterministic_genesis_keypair
crypto_helper::genesis::tests ‑ test_generate_test_non_deterministic_genesis_keypair
entities::beacon::tests ‑ test_beacon_compare_to_older_different_network
entities::beacon::tests ‑ test_beacon_compare_to_older_epochs_greater
entities::beacon::tests ‑ test_beacon_compare_to_older_epochs_less
entities::beacon::tests ‑ test_beacon_compare_to_older_equal
entities::beacon::tests ‑ test_beacon_compare_to_older_lower_epoch_greater_immutable
…

♻️ This comment has been updated with latest results.