Support referencing dynamically named secrets

[winnie-opal]

Is your feature request related to a problem? Please describe.
When using ld-relay-helm as a subchart, I can't reference dynamically-named secrets because Helm values files don't support templating. This is preventing me from passing secrets from other subcharts like Redis that use {{ .Release.Name }} in their secret names.

Describe the solution you'd like
Add tpl function support to secret references, similar to how Bitnami and other popular Helm charts handle this pattern, e.g. https://github.com/bitnami/charts/blob/21693ad18f84cd3c14daacd4f1da5ee9c3ea162f/bitnami/redis/templates/_helpers.tpl#L181-L190

{{- range .Values.relay.secrets }}
              {{- if .envName }}
            - name: {{ .envName }}
              valueFrom:
                  secretKeyRef:
                    key: {{ tpl .secretKey }}
                    name: {{ tpl .secretName }}

Describe alternatives you've considered
One alternative is creating a statically named secret that I can reference. However, this is an anti-pattern in Helm because it would prevent multiple Helm deployments from existing in the same namespace.

[keelerm84]

Thank you for raising this feature request.

This does look like a neat use case, and something we can explore supporting. I don't have a timeline on when we might be able to deliver this work. However, we do always welcome external contributions, if that's something you're interested in. Otherwise, I will update you here once the work has been completed.

Tracking internally as SDK-1912.