Show all known identiers in an invitation (display name, username, fingerprint)

Suggestion

In an invitation, show (if available) all the following:

1. Profile picture
2. Display name
3. Username (if registered either in a public instance or on a JAMS instance)
4. Fingerprint (i.e. hash)
5. QR code
6. Name server address
   (a) ns.jami.net (if public instance)
   (b) https://jams.domain.com/api/nameserver (if JAMS instance)

@choffmann is a design required?

Scenario

1. Send an invitation
2. Person responds in Jami chat with:

Sorry but who are you?

3. Write a chat message stating who you are
4. Jami chat reply is:

It's just that I only have the hash in the invitation, so I couldn't figure out who it was.

Thank you

Cf. #1835

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