docs/document how to setup hf oauth

[sdiazlor]

Pull Request Template

COMMENTS:

• I'm not sure about the index shown due to the installation.md file (as it encompass the library installation, mention the server and some developer info), maybe it would be useful to also add a basic docker.md as they are the two basic ways of deploying.
• I also thought of mentioning that they can use Oauth with other apps, but while we don't add other type of deployments (community ones) I decided not to confuse.

Closes #5091

Type of change

• Documentation update

How Has This Been Tested

mkdocs serve

Checklist

• I added relevant documentation