feat: introduce GatewayConfig CRD for gateway-scoped configuration

This commit adds the GatewayConfig custom resource definition (CRD) to manage configuration for the AI Gateway external processor. It allows users to define environment variables and resource requirements at the gateway level, enhancing flexibility and reusability across multiple gateways. The AIGatewayRoute's resource configuration is now deprecated in favor of this new approach.

Additionally, the GatewayConfig controller is implemented to handle the lifecycle of GatewayConfig resources, including finalizer management to prevent accidental deletions while still referenced by Gateways.

Documentation updates are included to reflect the new configuration options and migration guidance from the deprecated route-level settings.

Signed-off-by: Shabab Qaisar <[email protected]>
Signed-off-by: Shabab Qaisar <[email protected]>

Author: sqaisar

api/v1alpha1/ai_gateway_route.go

@@ -400,6 +400,11 @@ type AIGatewayFilterConfigExternalProcessor struct {
 	// Resources required by the external processor container.
 	// More info: https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/
 	//
+	// Deprecated: Use GatewayConfig for gateway-scoped resource configuration instead.
+	// Configure resources using GatewayConfig.spec.extProc.resources and reference it
+	// from the Gateway via the "aigateway.envoyproxy.io/gateway-config" annotation.
+	// This field will be removed in a future version.
+	//
 	// Note: when multiple AIGatewayRoute resources are attached to the same Gateway, and each
 	// AIGatewayRoute has a different resource configuration, the ai-gateway will pick one of them
 	// to configure the resource requirements of the external processor container.