Heron Helm chart should use `appVersion` based on Helm best practices

[nicknezis]

Is your feature request related to a problem? Please describe. In Helm there is a version field that describes the Helm chart. There is also an appVersion that is an optional informational field that describes the application the chart installs. Our Helm chart should be updated to include this field and reference it in the appropriate places in the template.

[joshfischer1108]

Should this be address before the next release candidate?