Glob support for runtimeconfig path.

[jeschkies]

I would like to add Glob support to the runtimeconfig file paths, e.g. /etc/my-app/*.yaml would load all YAMLS files in alphabetical order in directory /etc/my-app/.

Motivation

Allows empty directories I'm mounting a ConfigMap as optional. This means a config file might not be present at the beginning.

Allows hierarchical loading One can have a folder with files config-001.yaml, config-003.yaml etc.

[matryer]

Nice idea. These days I usually start with Glob support whenever a cli takes a path.