[deployment][helm] Add Grafana ingress template

[roman-popenov]

Motivation

Exposing Grafana via soft ingress controller so that it can be exposed through a Load Balancer.

Proposed solution:

Create ingress template for Grafana so that it can be automatically picked up if ingress controller instance is running in the cluster. The other solutions are to expose Grafana as NodePort or setting it as a LoadBalancer.

Modifications

Added grafana-ingress.yaml template in the templates and an ingress section for Grafana in the values file.

Verifying this change

1. Set ingress to true for Grafana in values file and provide hostname. Currently tested with NGINX, but can use another ingress controller, but will need to change the ingress controller class to another one in the template.

2. Add NGINX Helm repository :

helm repo add nginx-stable https://helm.nginx.com/stable
helm repo update

3. Install with Helm 3:

helm install nginix-ingress-crl nginx-stable/nginx-ingress

4. Follow the instructions on how deploying helm and run:
   helm install pulsar --values pulsar/values-mini.yaml ./pulsar/.

5. Wait until all the services are up and running.

6. Verify that Grafana is accessible via url.

Path settings

Currently, by default the path setting is set to /grafana. For that to work, the NGINX configuration file nginx.conf should have grafana sub path enabled:

See https://grafana.com/docs/grafana/latest/installation/behind_proxy/

To avoid having to mess with NGINX configurations files `path` can be changed to `/`, but this path might conflict with other services that are being proxied in the cluster.

#### Modules affected:
The changes in the PR are affecting the deployment using the helm charts. Now the if the flag `functionsAsPods` is set to `yes` inside the `values.yaml. file, the functions would run as pods.

### Documentation
This PR will be adding ingress capability for Grafana and this should be documented.