docs: ingester-design.md incorrectly claims ingester watches 13 CRDs (actually 0 since PR #1012)

[sallycr]

Section 1 claims the ingester watches all 13 CRDs. Incorrect since PR #1012 emptied the registration loop in go/components/ingester/module.go (crdObjects := []runtime.Object{}). Zero reconcilers are registered. Section 5.6 is TODO(#1011) because the old AllCRDObjects mechanism no longer exists. Operators enabling the ingester will see no MySQL syncing. Needs: (1) doc update reflecting current state, (2) new CRD registration mechanism design, (3) complete section 5.6.