Prepare API for alternative ETH node implementations

[pedropombeiro]

Currently, there are areas in the code that leak Geth types, making it impossible to have status-protocol-go work with e.g. Nimbus.

Issues

• [x] NewMessenger is receiving a Geth type *whisper.Whisper;
• [x] whisper.BytesToTopic needs to be encapsulated;
• [x] WhisperServiceTransport.RetrieveAllMessages is returning a Geth type (*whisper.ReceivedMessage), tying the consuming class Messenger to Geth;
• [x] messageProcessor.Process receives *whisper.ReceivedMessage.

Implementation

To fix that we need to create interfaces/wrappers for:

• [x] whisper.Whisper
• [x] whisper.PublicWhisperAPI
• [x] whisper.Filter
  • [x] Factory method on Whisper interface that creates appropriate Filter wrapper object instances
• [x] whisper.NewMessage
• [x] whisper.ReceivedMessage
• [x] whisper.MessageStore
• [x] whisper.BytesToTopic
• [x] Fix tests
• Optional:
  • [x] envelopesMonitorConfig

Next steps

• Implement Nimbus support
• Have status-console-client work on top of Nimbus

cc @adambabik @cammellos

[pedropombeiro]

@cammellos / @adambabik status-console-client seems quite out of date (master is 2 months old). There is an upgrade-status-protocol-go but that one also points to a non-existing status-protocol-go commit.

[pedropombeiro]

OK, I've updated it to the latest status-protocol-go and pushed it to a branch

[adambabik]

Yeah, NewMessenger is called from anything that wants to use status-protocol-go. Generally, any public interface changes in the main package of status-protocol-go can potentially break something at this point.