apps: dropping some falco rules

[viktor-f]

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What kind of PR is this?

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• kind/feature
• kind/improvement
• kind/deprecation
• kind/documentation
• kind/clean-up
• kind/bug
• kind/other

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Important

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What does this PR do / why do we need this PR?

Based on this internal product management discussion.

This PR drops a few falco rules and removes some of our special modifications to those rules.

Dropping these rules since they are a relatively weak indication of intrusion. They would also require a significant amount of tuning before they are really useful.

• Read sensitive file trusted after startup
• Read sensitive file untrusted

Dropping these rules since they produce significant spam due to false positives. For the same reasons they are also not a strong indication of intrusion.

• Terminal shell in container
• Contact K8S API Server From Container
• Redirect STDOUT/STDIN to Network Connection in Container

Information to reviewers

Checklist

• Proper commit message prefix on all commits
• Change checks:
  • The change is transparent
  • The change is disruptive
  • The change requires no migration steps
  • The change requires migration steps
  • The change upgrades CRDs
  • The change updates the config and the schema
• Documentation checks:
  • The public documentation required no updates
  • The public documentation required an update - [link to change](set-me)
• Metrics checks:
  • The metrics are still exposed and present in Grafana after the change
  • The metrics names didn't change (Grafana dashboards and Prometheus alerts are not affected)
  • The metrics names did change (Grafana dashboards and Prometheus alerts were fixed)
• Logs checks:
  • The logs do not show any errors after the change
• Pod Security Policy checks:
  • Any changed pod is covered by Pod Security Admission
  • Any changed pod is covered by Gatekeeper Pod Security Policies
  • The change does not cause any pods to be blocked by Pod Security Admission or Policies
• Network Policy checks:
  • Any changed pod is covered by Network Policies
  • The change does not cause any dropped packets in the NetworkPolicy Dashboard
• Audit checks:
  • The change does not cause any unnecessary Kubernetes audit events
  • The change requires changes to Kubernetes audit policy
• Falco checks:
  • The change does not cause any alerts to be generated by Falco
• Bug checks:
  • The bug fix is covered by regression tests