Test inference endpoint model config parsing from path (#434)
* Add example model config for existing endpoint
* Test InferenceEndpointModelConfig.from_path
* Comment default main branch in example
* Fix typo
* Delete unused add_special_tokens param in endpoint example config
* Fix typo
* Implement InferenceEndpointModelConfig.from_path
* Use InferenceEndpointModelConfig.from_path
* Refactor InferenceEndpointModelConfig.from_path
* Align docs