[td-agent] monit.log監視用の設定ファイルを追加する

## Manager側
```
<match fwd.raw.monit>
  type rewrite_tag_filter

  rewriterule1 hostname (.+) tmp.monit.$1
</match>

<match tmp.monit.*>
  type forest
  subtype grep

  remove_prefix tmp.monit

  <template>
    input_key message
    regexp (error|ERROR)

    add_tag_prefix notification
  </template>
</match>
```

## agent側
```
<source>
  type tail
  path /var/log/monit.log
  pos_file /var/log/td-agent/monit.pos
  format none
  tag raw.monit
</source>

<match raw.monit>
  type record_reformer
  enable_ruby false
  tag fwd.raw.monit
  <record>
    hostname  ${hostname}
  </record>
</match>
```