Enable returning error when configurations in the input data are not in standardized format

[everjing]

Currently binary returns "[]" when configurations in the input data are not in standardized format,
such as

targets:

• paths:
  • ./data
    policies:
  • ./policy

instead of

files:

• paths:
  • ./data
    policies:
  • ./policy

It is recommended to invoke a check loaded configurations from input data against standardized input format and return error when the two are not matching.