Feature: Bad Format exception

# Feature request for Cloudinary Python SDK

## Explain your use case
At the moment, specifying allowed_formats only raises a general Error when the file is of the wrong file type: ie: Raw file format txt not allowed

## Describe the problem you’re trying to solve
Having a specific type of exception such as BadFormat/BadFileType would allow us to handle it in a cleaner fashion.

## Do you have a proposed solution?
Yes, implement an exception which is raised if the server returns a certain type of error.