refactor: associate chats to pubsub topics and populate these depending if the chat belongs to a community or not
refactor: add pubsub topic to mailserver batches
chore: ensure default relay messages continue working as they should
refactor: mailserver functions should be aware of pubsub topics
fix: use []byte for communityIDs
Usually, message IDs are generated by their payload and signature and
in receiving nodes calculated in based on the same data as well.
There's no ID attached to messages in-flight.
This turns out to be a bit of a problem for messages that are being
imported from third party systems like discord, as the conversion
and saving of such messages and handling of their possible assets and
attachments are done in separate steps, which changes the message
payloads after their IDs have been generated.
Hence, we're introducing a `ThirdPartyID` property to `common.Message`
and `protobuf.WakuMessage` so receiving nodes of such messages (via the
archive protocol primarily) can easily detect third party/imported
messages and give them special treatment.
Richard Ramos
Pascal Precht
Adam Babik
Pedro Pombeiro