[User Story] - notation cert CRUD

[dtzar]

As a user, I want to add/list/update/delete (CRUD) certificates.

Implementation items to complete story:

• [ ] https://github.com/notaryproject/notation/issues/225
• [ ] https://github.com/notaryproject/notaryproject/issues/144

[yizha1]

How about command notation cert generate-test, which generates a test RSA key and a corresponding self-signed certificate? With this command, user can easily try notation sign & verify for testing purpose, see example showed in this document https://github.com/notaryproject/notation/blob/main/docs/hello-signing.md

[yizha1]

This issue is part of #38, recommend milestone rc.1

[priteshbandi]

This has been already implemented in RC1.