* Use a single Message type `v1/message.go` and `message.go` are the same now, and they embed `protobuf.ChatMessage`
* Use `SendChatMessage` for sending chat messages, this is basically the old `Send` but a bit more flexible so we can send different message types (stickers,commands), and not just text.
* Remove dedup from services/shhext. Because now we process in status-protocol, dedup makes less sense, as those messages are going to be processed anyway, so removing for now, we can re-evaluate if bringing it to status-go or not.
* Change the various retrieveX method to a single one:
`RetrieveAll` will be processing those messages that it can process (Currently only `Message`), and return the rest in `RawMessages` (still transit). The format for the response is:
`Chats`: -> The chats updated by receiving the message
`Messages`: -> The messages retrieved (already matched to a chat)
`Contacts`: -> The contacts updated by the messages
`RawMessages` -> Anything else that can't be parsed, eventually as we move everything to status-protocol-go this will go away.
Wallet database refactored so that every query ensures isolation by the network id.
Network id provided when database object is created, thus it is transparent to other parts
of the wallet module.
Additionally every uniqueness index is changed to ensure that it doesn't prevent adding
object with same id but from a different network.