Add BERT resources
This PR kicks off #19848 and adds official resources for BERT to the BERT model doc page. The resources are grouped by the types of tasks you can use the model for as well as using it for some other applications like inference and deployment.

If possible, I think it'd also be cool to use the task icons we use on the Hub and Tasks page (see below for example). What do you think?

![Screen Shot 2022-10-24 at 1 26 25 PM](https://user-images.githubusercontent.com/59462357/197622917-a9978857-e0b4-4d42-b066-a4b44574c792.png)
_The documentation is not available anymore as the PR was closed or merged._<|||||>I really like this!<|||||>Awesome, I'll start on some of the other models then! In the meantime, I'll check with @mishig25 if we can use the icons in the docs :)<|||||>We don't have an icon for multiple choice, so would it be ok to add it under question answering (since its kind of a variant of question answering)?<|||||>It's more a variant of sequence classification technically.<|||||>Ah ok! Would it be too confusing to include it under sequence classification then? We can also just leave it as is 😄