Update model share tutorial
First draft of the updated model sharing tutorial. Main updates include:

- Suggest converting a model to other frameworks before uploading it to the Hub.
- Advocate for `push_to_hub` as best practice for uploading files to the Hub. Most notably, the `transformers-cli` method has been removed. Would love your thoughts on whether we should include using the web interface to share models so this step is more accessible a wider background of users!
_The documentation is not available anymore as the PR was closed or merged._<|||||>yes i would advocate to include using the web interface to share models