no loadbalancerIP for service

**Describe the bug**
https://github.com/apache/couchdb-helm/blob/master/couchdb/templates/service.yaml

There is no option of loadbalancerIP

We should have something like

```yml
{{- if eq .Values.service.type "LoadBalancer" }}
{{- if not (empty .Values.service.loadBalancerIP) }}
loadBalancerIP: {{ .Values.service.loadBalancerIP }}
{{- end }}
{{- if .Values.service.loadBalancerSourceRanges }}
loadBalancerSourceRanges: {{- toYaml .Values.service.loadBalancerSourceRanges | nindent 4 }}
{{- end }}
{{- end }}
{{- if .Values.service.externalIPs }}
externalIPs: {{- toYaml .Values.service.externalIPs | nindent 4 }}
{{- end }}
```