son-gui and LOGS_URL

[felipevicens]

This url should be configured in case you have a graylog system conected to SONATA.

The IP address should be different to public_ip. Something like graylog_ip if this exists.

[arocha7]

Question: are there a Graylog server available to SP?

Changes included:

• roles/sp/tasks/gtk/gui.yml
  LOGS_URL: "{{ graylog_ip }}:12900"
• roles/sp/vars/main.yml
  graylog_ip: 172.31.6.??