helm_lib_prometheus_rules_recursion with optional filter

[borg-z]

Added optional filename filter, backward compatibility is preserved
Example:

{{- $prometheusRules := list
  "monitoring/prometheus-rules/caps-nodes.tpl"
  "monitoring/prometheus-rules/cloud-data-discovery.tpl"
}}

{{- if include "cluster_autoscaler_enabled" . }}
  {{- $prometheusRules = append $prometheusRules "monitoring/prometheus-rules/cluster-autoscaler.tpl" }}
{{- end }}

{{- include "helm_lib_prometheus_rules" (list . "d8-cloud-instance-manager" $prometheusRules) }}