Support yaml multi-doc config files

[jframe]

Add support for yaml multidoc config files so that a single config file can be used rather than multiple config files. This would make it easier to configure particularly in a kubernetes environment where providing multiple files would mean changing the k8s config each time.

[usmansaleem]

Dev note: Reloading of config file changes. Consider using hash of file to monitor file changes ? Will it work in K8?