Add fluentd support

Change-Id: I64a93135daebe7d55430adc51de2c9186c7a5ad7

linux/meta/fluentd.yml

+config:
+  label:
+    systemd:
+      input:
+        systemd:
+          type: systemd
+          tag: systemd.source
+          path: /run/log/journal
+          pos_file: /tmp/fluentd-systemd.pos
+          entry:
+            field_map:
+              MESSAGE: 'Payload'
+              _CMDLINE: 'process'
+              _PID: 'Pid'
+              _COMM: 'programname'
+              _SYSTEMD_UNIT: 'service'
+              syslog_identifier: 'ident'
+              priority: 'Severity'
+            field_map_strict: True
+            fields_strip_underscores: True
+            fields_lowercase: True
+      filter:
+        add_severity_label:
+          tag: systemd.source
+          type: record_transformer
+          enable_ruby: true
+          record:
+            - name: severity_label
+              value: '${ {"TRACE"=>8,"DEBUG"=>7,"INFO"=>6,"NOTICE"=>5,"WARNING"=>4,"ERROR"=>3,"CRITICAL"=>2,"ALERT"=>1,"EMERGENCY"=>0}.key(record["Severity"].to_i) }'
+      match:
+        rewrite_tag:
+          tag: systemd.source
+          type: rewrite_tag_filter
+          rule:
+            - name: service
+              regexp: '^(.*)\.(.*)$'
+              result: __TAG__.$1
+        push_to_default:
+          tag: 'systemd.source.*'
+          type: relabel
+          label: default_output

metadata/service/support.yml

         enabled: true
       grafana:
         enabled: true
+      fluentd:
+        enabled: true