Enable by compiling with -d:p2pdump. A chronicles log file named
p2p_messages.json will be created in the working directory. This
file will be consumed by the upcoming Chronicles Tail GUI (more
details will be provided on the wiki of this repo).
Other changes:
* Removes the use of package_visible_types (only partially so far)
* Simplifies the new Snappy code a little bit
This also restores the old module structure of having separate
`peer_pool` and `rlpx` modules. This is made possible by the
new Nim package `package_visible_types` (please refer to its
README for an explanation).
Also introduces more error handling in the low-level RLPx routines.
All detected errors will result in immediate disconnection of the
corresponding peer, which may be detected in the protocols though
the `onPeerDisconnected` event handler.
