This commit moves group chats to their own topic, based on the randomly
generated chat-id. It falls back on the discovery topic for those peers
who we can't fingerprint the version, for backward compatibility.
Members will now have to explicitly join a group chat to start receiving
messages from it.
Messages are still sent to users who have not joined for backward
compatibility.
Group updates are unaffected.
Implementation:
1. `transport.utils/message-id` function is called only in three places now
and accepts `from` and `raw_payload` as parameters.
ID is calculated as `sha3(from + raw_payload)`.
2. This means that for wrapped private group chat message
the raw payload of `GroupMembershipUpdate` is used.
Adds a `chat-id` field in `content` map.
The reason it has been added to the map instead of augmenting transit is
that it would simplify the calculation of `message-id`, which in this
case is consistent for both old & new clients.
`chat-id` also represents the `chat-id` with respect of the sender, as
in 1-to-1 chats that is asymmetric.
Signed-off-by: Andrea Maria Piana <andrea.maria.piana@gmail.com>
Andrea Maria Piana
Roman Volosovskyi
Eric Dvorsak
janherich