feature: plugin topology

Summary

• feature: plugin topology

Plugin topology is a mapping plugin service to tiers.

Introduce new pico.update_plugin_tiers API. This function may be used for control where plugin services must be running and where not.

Plugin integration tests have also been refactored.

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• Changes should be cherry-picked to 24.2: no
• Docs follow-up: docs#237, docs#238, docs#239