Scale testing

This issue provides an overview over ongoing and upcoming tasks around scale testing.

## v1.15

Scale:

* Misc:
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13803
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/14075
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/14076
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/14084
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/14085

## v1.14

Scale:

* Misc:
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13807

Scale testing:

## v1.13

Scale:
* PriorityQueue
* [x] [Reconcile latency] https://github.com/kubernetes-sigs/cluster-api/pull/13171
* ReconcilerRateLimiting:
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13373
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13422
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13416
* Optimize cache configuration
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13407
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13460
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13488
* Admission webhook improvements:
* [x] [Memory] CR: https://github.com/kubernetes-sigs/controller-runtime/pull/3463
* Conversion webhook improvements:
* [x] [Memory] conversion/convert gets called a lot for unserved versions (even though we never use old apiVersions) https://github.com/kubernetes/kubernetes/pull/130704
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13402
* Patch helper improvements:
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13365
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13364
* [x] [Memory] https://github.com/kubernetes-sigs/cluster-api/pull/13367
* [x] [Reduce apiserver calls] https://github.com/kubernetes-sigs/cluster-api/pull/13403
* Misc:
* [x] [Reduce apiserver calls] https://github.com/kubernetes-sigs/cluster-api/pull/13401
* [x] [Reduce apiserver calls] https://github.com/kubernetes-sigs/cluster-api/pull/13457
* [x] [Reduce apiserver calls] https://github.com/kubernetes-sigs/cluster-api/pull/13458
* [x] [Reduce apiserver calls] https://github.com/kubernetes-sigs/cluster-api/pull/13459
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13496

* Reduce log verbosity:
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13396
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13420
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13421

Scale testing:
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13304
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13306
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13354
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13361
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13423
* [x] https://github.com/kubernetes-sigs/cluster-api/pull/13492
* [ ] Improve hot restarts in CAPDev
* See changes to test/infrastructure/vcsim/controllers in https://github.com/kubernetes-sigs/cluster-api-provider-vsphere/pull/3878

## Potential follow-ups

* [ ] Consider introducing a direct link between syncPeriod and SSA cache TTL: https://github.com/kubernetes-sigs/cluster-api/pull/13459#discussion_r2939763740
* [ ] Consider caching earlier in dryrun.go: https://github.com/kubernetes-sigs/cluster-api/pull/13459#discussion_r2939830729