feat(keycloakx): make relabelings possible on serviceMonitors

[wilmardo]

Allow settings relabelings on the ServiceMonitors. My usecase is to show the pod names instead of the IPs in a dashboard and this is one of the easiest ways. Just add a relabel in the serviceMonitor.
For completeness I added the metricRelabelings as well.
But this is probably useful for other things is well, this PR just makes the existing fields available for the helm chart user.

Quick local test copy paste:

Values file:

serviceMonitor:
  enabled: true
  relabelings:
    - action: replace
      regex: (.*)
      sourceLabels: [__meta_kubernetes_pod_name]
      targetLabel: instance
  metricRelabelings:
    - action: drop
      regex: jvm_.+
      sourceLabels:
      - __name__

helm template test charts/keycloakx -f test.yml -s templates/servicemonitor.yaml

---
# Source: keycloakx/templates/servicemonitor.yaml
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: test-keycloakx-keycloakx
  namespace: default
  labels:
    helm.sh/chart: keycloakx-7.0.1
    app.kubernetes.io/name: keycloakx
    app.kubernetes.io/instance: test
    app.kubernetes.io/version: "26.0.7"
    app.kubernetes.io/managed-by: Helm
spec:
  selector:
    matchLabels:
      app.kubernetes.io/name: keycloakx
      app.kubernetes.io/instance: test
      app.kubernetes.io/component: http
  endpoints:
    - port: "http-internal"
      path: "/auth/metrics"
      scheme: http
      interval: 10s
      scrapeTimeout: 10s
      relabelings:
        - action: replace
          regex: (.*)
          sourceLabels:
          - __meta_kubernetes_pod_name
          targetLabel: instance
      metricRelabelings:
        - action: drop
          regex: jvm_.+
          sourceLabels:
          - __name__