Add support for metrics and pprof (#100)

Adds support for toggling support for `pprof` and metrics:

```yaml
gitea:
  pprofEnabled: true

  metrics:
    enabled: true
    serviceMonitor:
      enabled: true
```

Co-authored-by: josef <josef.nilsen@outlook.com>
Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/100
Reviewed-by: luhahn <luhahn@noreply.gitea.io>
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: JosefWN <josefwn@noreply.gitea.io>
Co-committed-by: JosefWN <josefwn@noreply.gitea.io>

templates/gitea/statefulset.yaml

@@ -66,6 +66,10 @@ spec:
               containerPort: {{ .Values.gitea.config.server.SSH_LISTEN_PORT }}
             - name: http
               containerPort: {{ .Values.gitea.config.server.HTTP_PORT }}
+            {{- if .Values.gitea.config.server.PPROF_ENABLED }}
+            - name: profiler
+              containerPort: 6060
+            {{- end }}
           livenessProbe:
             tcpSocket:
               port: http