PIP-746: Added 'json' logging handler

[thrawn01]

Purpose

kafka-pixy now supports context based logging via stdout, additionally you can configure logging via yaml file passed via -config

# A list of defined loggers, multiple loggers are allowed and 
# each log line will be sent to every logger defined
logging:
  # Logs to stdout in a JSON format
  - name: json
    severity: info
  # Logs to stdout in human readable format
  - name: console
    severity: info
  # Logs to kafka topic in JSON format
  - name: udplog
    severity: error
  # Logs to syslog
  - name: syslog
    severity: debug

Implementation

• --logging can be used to override the logging config provided via the config file