Allow yaml to include a list of tags that will be applied to a specific include.

This patch allows a list of tags to be applied to a specific include, like so:
```yaml
 - include:
   domain: '"kafka.server"'
   type: '"BrokerTopicMetrics"'
   name: '"buckets-BytesInPerSec"'
   attribute:
      OneMinuteRate:
        alias: kafka.net.bytes_in.1
        tags:
          - "topic:buckets"
```

This is very helpful for places where JMX names/attributes/whatever don't line up with convenient tags.
Sorry? What's not useful?