QA: 200-node test

[sergio-mena]

Run the 200-node test as specified in RELEASES.md (using the infra in qa-infra), fix any found issue, compare with v0.37.0 results. Finally populate the 200 node section of the v0.38.x report.

• Set up the DO testbed
• Run the tests: loader process in a nested for loop (TX load and number of connections)
• Analyze latencies to find the TX saturation point
  • Obtain the plots of latencies
• Obtain the Prometheus plots for the load at the saturation point
  • Compare them to those obtained for v0.37.0
• Write corresponding section of the QA report

DoD:

• No showstopper bugs found remain unresolved
• 200-node section of the QA report is merged into main and v0.38.x
• No unacceptable performance regression detected (usually > 10% degradation w.r.t. v0.37.0