Description:
in order to optimize EG occupy high memory, #1610 supports EG watching the spec namespace. but the users need to list all namespaces that need watching. It's not convenient, we can watch the namespace that has some label. IMO should watch the namespace with the same label, like shared-gateway-access https://gateway-api.sigs.k8s.io/guides/multiple-ns/

xref: https://pkg.go.dev/sigs.k8s.io/controller-runtime@v0.15.0/pkg/cache#Options

cc @arkodg