Add CatalogSource including index with OSP nightly build

Here we only add the CatalogSource, but does not make use of it (does
not reference it in the kustomization.yaml). An automation job will
be including that reference until we switch to nightly builds.

operator/gitops/argocd/pipeline-service/openshift-pipelines/osp-nightly-catalog-source.yaml

@@ -0,0 +1,15 @@
+---
+apiVersion: operators.coreos.com/v1alpha1
+kind: CatalogSource
+metadata:
+  name: custom-operators
+  namespace: openshift-marketplace
+  annotations:
+    argocd.argoproj.io/sync-wave: "0"
+spec:
+  sourceType: grpc
+  image: quay.io/openshift-pipeline/openshift-pipelines-pipelines-operator-bundle-container-index@sha256:d1e530ade1cd223947e82bf46d4a8274a61aab4fca3fff842e46e667914df900
+  displayName: custom-operators
+  updateStrategy:
+    registryPoll:
+      interval: 30m