with PR #1101 changes have been made to packetbeat protocol registration, turning the guide somewhat out of data. Plus we might want to provide some cookiecutter templates for generating boilerplate code.

checklist:

• ProtocolPlugin has been renamed to Plugin
• TcpProtocolPlugin has been renamed to TcpPlugin
• UdpProtocolPlugin has been renamed to UdpPlugin
• configuration local to plugin in config.go, based on ucfg. No changes in packetbeat/config/config.go required.
• fields.yml to become local to each protocol (see Packetbeat: fields.yml per protocol #1110)
• protocol registration via protos.Register (no more EnabledPlugins in packetbeat.go)
• optional: mention or create doc based on cookiecutter (still in progress) templates (different templates based on protocols) => explain templates