Add better logging

[kenmoini]

Ability to log to multiple standard facilities, eg:

pilot_light:
  logging:
    - mode: stdout
      sinks:
        - name: sys_stdout
          target: stdout
        - name: file_stdout
          target: /var/log/pilot-light.log
    - mode: stderr
      sinks:
        - name: sys_stderr
          target: stderr
        - name: file_stderr
          target: /var/log/pilot-light-errors.log

Or something, idk, how does journald work again?