[Pailot-P0] SPIKE: Investigate adding chat functionality for transactions

[vyktoremario]

We will have to add chat functionalities for each transaction, to help the parties involved (Sender, Courier and Receiver) communicate effectively while the transaction is ongoing.

We need to find out how:

1. Create a chat for every transaction that has been accepted by the courier
2. The three users involved in the transaction are part of the chat and can see each other messages.
3. The chat should be killed (or ended) when the transaction is marked as completed.

You can actually do a POC (Proof of concept) and open a PR if you need to.
Or you can just document your findings on this ticket.