appmesh-grafana allow to set grafana.ini.server.root_url

[sheetaljoshi]

Is your feature request related to a problem?
I am not able to access grafana via ALB sub path url.

Is your feature request related to a specific Helm chart, if yes mention name of the chart?
appmesh-grafana

Describe the solution you'd like
Please allow setting grafana.ini key-value pairs. Allow passing these values when install or upgrade. values.yaml needs to provide a placeholder and also config map template should read values.
https://github.com/helm/charts/blob/master/stable/grafana/templates/configmap.yaml

Describe alternatives you've considered
I am using a separarte ALB for grafana.