Add Awesome Performance Engineering to Performance section

[be-next]

Adds Awesome Performance Engineering to the Performance section.

This curated list covers the full spectrum of performance engineering tools:

• Observability — metrics, distributed tracing, logging, continuous profiling, alerting, and observability platforms
• Performance Testing — load & stress testing, HTTP benchmarking, chaos engineering, browser performance, CI/CD integration, and analysis

It complements the performance-related case studies already in this section by providing a tool-focused perspective on the discipline.