Convert iptables's edge processing to Ingest Node pipeline

[andrewkroh]

Convert edge processing to Ingest Node pipeline

This package uses Beats processors for some of its data processing. We want to
move that processing into the ingest node pipeline that is part of the package
to make reuse easier (e.g. data from Kafka could be routed through the pipeline).

Data Streams

• log (inputs: log, syslog)
  • All beats processors are removed
  • Pipeline tests added

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[andrewkroh]

The syslog input should be replaced with udp/tcp so that the processing of the various syslog headers happens in ingest node.