Push helm chart to registry

**User story**
As a user, I want to deploy the FHIR server with a helm chart published in a registry.

The helm chart should be pushed to ACR during PR builds and during CI build to allow users to pull directly from registry.

**Acceptance criteria**
1. When I do:

```
helm chart pull healthplatformregistry.azurecr.io/helm/fhir-server:latest
```

I will pull the helm chart to local registry.

Start by locating the Helm chart and the configuration for PR and CI builds. Trace how build artifacts are currently published, then determine where the chart should be pushed to ACR. Done means the documented helm chart pull command retrieves the latest chart from healthplatformregistry.azurecr.io.

Written by the indexing model from the issue text.