Hub process exits without an error message with empty hub.yaml

[cgetzen]

Describe the bug When hub starts with an empty hub.yaml, the container exits without printing an error.

Expected behavior An error message is printed that either includes one missing required viper config, or all missing required viper configs.

Additional context I suspect other components also do not print error messages.

[tegioz]

Thanks @cgetzen, we'll take care of this 👍