Open door for CLI to consume config file that autorest understands

As of today the CLI takes individual swagger and resolves it to pass it along to the breaking change tool. As autorest input is very flexible in also consuming the config files, we should allow the consumption of config files as well

**cc**
@olydis 👍 Thanks for pointing this out

Start by tracing how the CLI currently accepts an individual Swagger specification and passes it to the breaking change tool. Review how AutoRest config files are represented and resolved, then verify that the CLI can consume such a config and pass the resulting specifications through the existing flow.

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