Collect rabbitmq logs by fluentd

Change-Id: I49b24545501085d5a44f4de73f0c6dd21e06e2a0
Closes-Bug: #1835501

ansible/roles/common/templates/conf/input/03-rabbitmq.conf.j2

 <source>
   @type tail
-  path /var/log/kolla/rabbitmq/rabbit.log
+  path /var/log/kolla/rabbitmq/rabbit@{{ ansible_hostname }}.log
   pos_file /var/run/{{ fluentd_binary }}/rabbit.pos
   tag infra.rabbit
   format multiline
-  format_firstline /^\s*$/
-  format1 /^=(?<log_level>\w+) REPORT==== (?<Times>[^ ]+) ===\n/
-  format2 /^(?<Payload>.*)/
+  format_firstline /^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{3}/
+  format1 /^(?<Timestamp>\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}\.\d{3}) \[(?<log_level>\w+)\] (?<Payload>.*)/
   enable_watch_timer false
 </source>