Load config from k8s configmap

[qs-wang]

While running on edge cluster, i.e. k3s, not not want to use centralized registry service. However use local file seems not ideal either. Would be a useful feature to support loading config from k8s configmap

[jiekechoo]

@qs-wang Here is a few examples about configmap in the Helm Chart. https://github.com/edgexfoundry/edgex-helm/tree/main/templates/configmaps