feat: LRU cache for flows in packetparser

[nddq]

Description

This PR optimizes the packetparser plugin by introducing an LRU cache to reduce memory and CPU usage under heavy traffic. Instead of generating a new Flow object for each packet event, the cache stores Flow objects based on source/destination IPs, ports, protocol, and direction. Packet events with matching values will reuse the existing Flow object, preventing excessive ToFlow invocations and potential OOM kills for the agent.

Related Issue

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Checklist

• I have read the contributing documentation.
• I signed and signed-off the commits (git commit -S -s ...). See this documentation on signing commits.
• I have correctly attributed the author(s) of the code.
• I have tested the changes locally.
• I have followed the project's style guidelines.
• I have updated the documentation, if necessary.
• I have added tests, if applicable.

Screenshots (if applicable) or Testing Completed

Over a similar period of time under the same workload, the total memory allocation for ToFlow without cache

vs with cache

Please add any relevant screenshots or GIFs to showcase the changes made.

Additional Notes

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This PR will be closed in 7 days due to inactivity.

[github-actions]

Pull request closed due to inactivity.