add new plugin sections

Summary

• add 4 new plugin sections

  the new sections are not exposed in the index, only available via direct URLs

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• Close #344 (closed)
• Cherry-pick to: none
• Staging:
  • https://docs.binary.picodata.io/picodata/at_more_plugins/plugins/argus/
  • https://docs.binary.picodata.io/picodata/at_more_plugins/plugins/svarog/
  • https://docs.binary.picodata.io/picodata/at_more_plugins/plugins/task/
  • https://docs.binary.picodata.io/picodata/at_more_plugins/plugins/uroboros/