cluster-components: Add support for alertmanager inhibitor rules

Related to swh/infra/sysadm-environment#5036

cluster-components/templates/alertmanager-config/config.yaml

@@ -6,6 +6,10 @@ metadata:
   name: irc-relay-config
   namespace: {{ .Values.alertmanagerConfig.namespace }}
 spec:
+  {{- if .Values.alertmanagerConfig.inhibitorRules }}
+  inhibitorRules:
+    {{- toYaml .Values.alertmanagerConfig.inhibitorRules | nindent 4 }}
+  {{- end }}
   route:
     groupBy: ['...']
     groupWait: 31s

cluster-components/values.yaml

@@ -35,6 +35,11 @@ alertmanagerConfig:
     secretRef: alertmanager-irc-relay-config
     userKeyRef: user
     passwordKeyRef: password
+  # inhibitorRules:
+  #   - targetMatch:
+  #     - name: mylabel
+  #       value: myvalue
+  #     ...
 
 alertmanagerIrcRelay:
   enabled: false