[Follow-up][Feature] Add L7 metrics

[LorenzoTettamanti]

Problem Description:

The actual metrics API expose L3-L4 kernel metrics to trace network packets, IPs and TCP,UDP connections. Real applications generates also L7 traffic via HTTPs, FTP, SSH,gRPC connections exposing API endpoints

Solution:

• Use syscalls and tracepoints to intercept L7 traffic.
• Create a metric in otel_metrics.rs file
• Submit a test (Docker or Kubernetes) in the PR to make sure that the new metrics are correctly intercepted

Additional info

• Discuss with the team before submitting a solution
• Useful files:
  • otel_metrics.rs
  • buffer_type.rs
  • kernel-space metrics tracer
  • user space metrics consumer