WIP Extra filter labels for prometheus dashboard

[palage4a]

If this pull request introduces support for new metrics, do not forget to

• [ ] add Grafana panel;
• [ ] run make update-tests to build new dashboard artifacts;
• [ ] add example application code to generate non-null metrics;
• [ ] attach a screenshot of a new panel to the PR description;
• [ ] add new Telegraf tag key, if relevant,
  • [ ] to all telegraf.conf files,
  • [ ] to "Grafana dashboard" documentation page;
• [ ] add alert example, if relevant,
  • [ ] to alerts.yml,
  • [ ] to "Alerting" documentation page;
• [ ] update supported_metrics.md.

In any case, do not forget to

• [ ] link an issue;
• [ ] add a CHANGELOG entry;
• [ ] update documentation guidelines;
• [ ] update README guidelines.

Closes #206

[DifferentialOrange]

Thank you for your patch. Solved by #211