GUI: Read receipts

[jzbz]

Most major messaging protocols/services such as Matrix, XMPP, Signal, iMessage, WhatsApp, Telegram offer read receipts by default and I think this would be especially useful for Bison Relay. Obviously the option to turn them off should remain to maximize privacy however I think they should probably be on by default given the possibility for broken ratchets leading to messages going undelivered. Ideally a system with one check for delivered to the server and two checks for delivered to the user's device and then coloring in the checks if they are actually read (See Signal for the best example of this).

[miki-totefu]

need confirmation if this should be done

@alexlyp @behindtext

[exitus1]

+1 to this.

I was under the impression such a thing wasn't possible on BR, but if it is, why not add it as an option.