Typing changes to persisted data

[jonasmalacofilho]

The idea is to group all desired typing changes here, for a future migration.

• add db.Metadata { name, value } (i.e. for storage of schemaVersion) (added in v1.1.0)
• add db.CardRequest.clientIp
• change CardRequested to CardRequested(client, card)
• combine db.CardRequest.<id> and dbRemoteCallLog.id to provide Meta.RecId to AcessoCard's APIs
• add db.CardRequest .startedAt/.requestedAt .created/.lastUpdated : Timestamp (added in v1.1.0)
• add db.RemoteCallLog .startedAt .created : Timestamp (added in v1.1.0)
• add CardRequestError.UnknownError
• add CardRequestError.LimitReached (cards/user limit, not global limit)

Note: no such migration is planned at the moment, so none of this might get implemented.

[jonasmalacofilho]

Closing; we're preparing for long-term (unassisted) operation (so no breaking changes desired) and a lot of requests have already been made without these changes.