feat(vector): split panos.yaml sinks into vector/sinks/ using automatic namespacing

[dr4gon123]

Summary

• Split all sinks from vector/panos.yaml into separate files under vector/sinks/ using Vector's automatic namespacing
• Each sink is now independently manageable (enable/disable by adding/removing the file)
• quickwit_panos and loki_panos were uncommented and moved to their own files
• Fixed stale panos.threat/content_type label in loki sink → replaced with panos.subtype

New files:

• vector/sinks/vlogs_panos.yaml — Victoria Logs
• vector/sinks/elastic_panos.yaml — Elasticsearch
• vector/sinks/quickwit_panos.yaml — Quickwit
• vector/sinks/loki_panos.yaml — Loki

Test plan

• vector validate --config-dir vector/ loads cleanly (tested in isolated temp dir)
• Run Vector against the config and send a test PAN-OS syslog to verify end-to-end

🤖 Generated with Claude Code