Add fluentd configuration for MySQL error.log

- changed default logging to log file
- parametrized log file path
- added fluentd configuration
- introduced fluentd multi_format parser plugin

Currently error logs sent to syslog are represented
with severity ERROR, which is misleading for Notice
and Warning messages during service startup/shutdown.

Change-Id: I55106775fa54b412b50ecc10c12930445da15d03
Related-bug: PROD-21904 (PROD:21904)
diff --git a/metadata/service/master/cluster.yml b/metadata/service/master/cluster.yml
index d48ffcb..af0bf1c 100644
--- a/metadata/service/master/cluster.yml
+++ b/metadata/service/master/cluster.yml
@@ -14,7 +14,8 @@
     galera_innodb_write_io_threads: 8
     galera_wsrep_slave_threads: 8
     galera_xtrabackup_parallel: 4
-    galera_error_log_enabled: false
+    galera_error_log_enabled: true
+    galera_error_log_path: /var/log/mysql/error.log
   galera:
     master:
       enabled: true
@@ -40,6 +41,7 @@
       wsrep_slave_threads: ${_param:galera_wsrep_slave_threads}
       xtrabackup_parallel: ${_param:galera_xtrabackup_parallel}
       error_log_enabled: ${_param:galera_error_log_enabled}
+      error_log_path: ${_param:galera_error_log_path}
   mysql:
     server:
       users: