docs: move pages from federation

[Meschreiber]

This PR moves some pages that are currently in the federation repo but appear in the Routing section of our docs.
This is a completion of the effort started here: #6157

[svc-apollo-docs]

✅ Docs Preview Ready

Configuration

{
  "repoOverrides": {
    "apollographql/router@main": {
      "remote": {
        "owner": "apollographql",
        "repo": "router",
        "branch": "docs/move-pages-from-federation"
      }
    }
  }
}

Name	Link
Commit	6849af4
Preview	https://www.apollographql.com/docs/deploy-preview/67cd1a0e2cd5d96c31c8
Build ID	67cd1a0e2cd5d96c31c8
File Changes	0 new, 1 changed, 0 removed * graphos/routing/about-router.mdx
Pages	1

---

1 pages published. Build will be available for 30 days.

[router-perf]

CI performance tests

• connectors-const - Connectors stress test that runs with a constant number of users
• const - Basic stress test that runs with a constant number of users
• demand-control-instrumented - A copy of the step test, but with demand control monitoring and metrics enabled
• demand-control-uninstrumented - A copy of the step test, but with demand control monitoring enabled
• enhanced-signature - Enhanced signature enabled
• events - Stress test for events with a lot of users and deduplication ENABLED
• events_big_cap_high_rate - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity
• events_big_cap_high_rate_callback - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity using callback mode
• events_callback - Stress test for events with a lot of users and deduplication ENABLED in callback mode
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• events_without_dedup_callback - Stress test for events with a lot of users and deduplication DISABLED using callback mode
• extended-reference-mode - Extended reference mode enabled
• large-request - Stress test with a 1 MB request payload
• no-tracing - Basic stress test, no tracing
• reload - Reload test over a long period of time at a constant rate of users
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• step-local-metrics - Field stats that are generated from the router rather than FTV1
• step-with-prometheus - A copy of the step test with the Prometheus metrics exporter enabled
• step - Basic stress test that steps up the number of users over time
• xlarge-request - Stress test with 10 MB request payload
• xxlarge-request - Stress test with 100 MB request payload

[shorgi]

approved pending broken links being fixed