Signer Verification Key store & adapters

[ghubertpalo]

In order to be able to persist signers verification key, here is a simple, modular and re-usable key / value store system.

[github-actions]

Unit Test Results

  6 files  ±  0  10 suites   - 5   2m 30s ⏱️ +6s
84 tests  - 19  84 ✔️  - 19  0 💤 ±0  0 ❌ ±0 

Results for commit 37a1df9. ± Comparison against base commit 9cfa79c.

This pull request removes 29 and adds 10 tests. Note that renamed tests count towards both.

aggregator::tests ‑ get_certificate_details_ko_404
aggregator::tests ‑ get_certificate_details_ko_500
aggregator::tests ‑ get_certificate_details_ko_unreachable
aggregator::tests ‑ get_certificate_details_ok
aggregator::tests ‑ get_download_snapshot_ko_500
aggregator::tests ‑ get_download_snapshot_ko_unreachable
aggregator::tests ‑ get_download_snapshot_ok
aggregator::tests ‑ get_snapshot_details_ko_404
aggregator::tests ‑ get_snapshot_details_ko_500
aggregator::tests ‑ get_snapshot_details_ko_unreachable
…

store::adapters::dumb_adapter::tests ‑ get_record_works
store::adapters::dumb_adapter::tests ‑ record_exists_works
store::adapters::dumb_adapter::tests ‑ store_record_works
store::adapters::memory_adapter::tests ‑ get_record_with_existing_key_work
store::adapters::memory_adapter::tests ‑ get_record_with_non_existing_key_work
store::adapters::memory_adapter::tests ‑ record_exists_works
store::adapters::memory_adapter::tests ‑ store_record_works
store::key_store::tests ‑ test_fetch_using_non_existent_key
store::key_store::tests ‑ test_fetch_verification_key
store::key_store::tests ‑ test_save_verification_key

♻️ This comment has been updated with latest results.

[ghubertpalo]

This PR is supersed by #182