Python-API based download and functionality.

Kaggle API provides a neat CLI to interact with the API. But, with my experience from working with Jupyter notebooks, and ML projects, I feel, If there was a way to instead use the Python API to download datasets easily, would have been of much help!

To explain, Let's say I want to download a Kaggle dataset. A function could be in the Python API which simplifies the downloading as follows,
`kaggle.download("")`

And this downloads the Dataset / Competition files, Auto unzips them and Prepares them for you. This could reduce work by a lot.

Now, For the Kaggle API authentication, We could have 3 steps for checking,
- Check if `~/kaggle.json` exists, If yes, Read the credentials.
- Check if the credentials are set in environmental variables, if yes, Load them.
- Finally, if none of them exists, Get the username with basic input, and Password with `getpass.getpass()`

The Python API could make it even more friendlier, approachable and better, As it reduces work with downloading and also performing other functions. I would like to work on this functionality initially, and extend it to further things (Converting commands into their Python API equivalent).

This would benefit a lot of people, and reduce their dependence on 3rd party packages which do this instead, and stick to this lightweight python package which does the work easy for them.