Remove BB created serviceMonitor and enable upstream ones

related #131 (closed)

chart/charts/gitlab/charts/gitlab-exporter/templates/bigbang/service-monitor.yaml

-{{- if .Values.enabled }}
-apiVersion: monitoring.coreos.com/v1
-kind: ServiceMonitor
-metadata:
-  name: {{ .Release.Name }}-metrics
-  namespace: {{ .Release.Namespace }}
-spec:
-  selector:
-    matchLabels:
-      app: gitlab-exporter
-  namespaceSelector:
-    matchNames:
-      - {{ .Release.Namespace }}
-  endpoints:
-    - path: /sidekiq 
-      interval: 30s
-      port: http-metrics
-      scheme: http
-  jobLabel: gitlab
-{{- end }}
\ No newline at end of file