ansible: Allow h-p to update scrape-collectd CM

The `scrape-collectd` ConfigMap in the `default` namespace is used by
Victoria Metrics to identif the hosts from which it should scrape
collectd metrics.  When deploying new machines that are _not_ part of
the Kubernetes cluster, we need to explicitly add them to this list.
The _host-provisioner_ can do this with an Ansible task, but it needs
the appropriate permissions to do so.

ansible/rbac.yaml

@@ -132,3 +132,38 @@ roleRef:
 subjects:
 - kind: ServiceAccount
   name: host-provisioner
+
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: host-provisioner
+  namespace: victoria-metrics
+  annotations:
+    kubernetes.io/description: >-
+      Allows the host-provisioner to update the scrape-collectd
+      ConfigMap when adding new hosts.
+rules:
+- apiGroups:
+  - ''
+  resources:
+  - configmaps
+  verbs:
+  - patch
+  - get
+  resourceNames:
+  - scrape-collectd
+
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: host-provisioner
+  namespace: victoria-metrics
+roleRef:
+  apiGroup: rbac.authorization.k8s.io
+  kind: Role
+  name: host-provisioner
+subjects:
+- kind: ServiceAccount
+  name: host-provisioner