support extended dnstap

[dmachard]

This feature add the support of the extended dnstap as proposed in #516

• atags
• filtering
• publicsuffix
• geoip

Additional metadata generated by various transformations such as filtering, atags, normalize and others will be added in the extra field with the DNSTap logger and properly decoded by the DNSTap collector

The new settings extended-support has been added for the dnstapclient and dnstap collector

  - name: central
    dnstapclient:
      transport: tcp
      remote-address: 127.0.0.1
      remote-port: 6002
      extended-support: true

If the extended-support is not enabled in the remote DNSCollector, the extra field will be decoded as string