docs: add QuotaPolicy capability guide #6024

Job	Run time
changes	9s
Controller Test (ubuntu-latest)	1m 45s
CRD CEL Validation Test (ubuntu-latest)	1m 17s
Unit Test (ubuntu-latest)	2m 23s
Data Plane MCP Test (ubuntu-latest)	6m 3s
Controller Test (macos-latest)	4m 15s
CRD CEL Validation Test (macos-latest)	4m 18s
Data Plane MCP Test (macos-latest)	5m 7s
Data Plane Test (ubuntu-latest)	5m 1s
E2E Test for Namespaced Controller	3m 41s
Unit Test (macos-latest)	6m 24s
Data Plane Test (macos-latest)	5m 24s
E2E Test (Envoy Gateway v1.8.1)	11m 33s
E2E Test (Envoy Gateway latest)	11m 25s
E2E Test for Inference Extensions	4m 23s
E2E Test for Upgrades (k8s v1.33.4)	14m 32s
E2E Test for aigw CLI	2m 41s
E2E Test for Upgrades (k8s v1.35.0)	13m 42s
E2E Test for Upgrades (k8s v1.32.8)	12m 16s
E2E Test for Upgrades (k8s v1.34.3)	13m 17s
ci-required	3s
Push Docker Images	-1s
Push Helm chart	-1s
	2h 9m 37s

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