UX: Activity and Inbox screens are confusing with Deferred Credential flow

[hacdias]

The Inbox and Activity screens are confusing at the moment. Sometimes they show the same information, but allow different options. The idea was:

• Activity: a log of everything that has happened. All the steps of a certain operation will be visible.
• Inbox: things that need your attention, pending credentials, DIDComm actions (?)

A case where it gets confusing is during deferred issuance. Then:

1. There's a "Card pending" item in Activity. This item stays there, even after the credential is received, because it works as an append-only log.
2. There's a "Card pending" item in Inbox. Here you can see when it'll be checked the next time, and also force-refresh to check if the credential is already ready.
3. The card doesn't show as pending in the cards list, as users would expect.

I think this is a good thing to revisit. Some ideas:

1. Show pending cards in Cards instead of Inbox
2. Activity should not be append-only. The "pending card" item should be removed once the credential issuance is completed/failed.
3. Merge Inbox and Activity. We'd need to see which DIDComm notifications we get there, I'm not sure.