Rename CLI to 'hf' + reorganize syntax

[Wauplin]

Closes #3224.
Partly inspired by #3225 but I preferred to start from scratch.

Goal is to rename huggingface-cli to hf + harmonize the syntax. We mostly follow a hf <resource> <action> [options] syntax similar to what's done by github CLI https://cli.github.com/manual/gh.

✗ hf --help
usage: hf <command> [<args>]

positional arguments:
  {auth,cache,download,repo,repo-files,upload,upload-large-folder,env,version,lfs-enable-largefiles,lfs-multipart-upload}
                        hf command helpers
    auth                Manage authentication (login, logout, etc.).
    cache               Manage local cache directory.
    download            Download files from the Hub
    repo                Manage repos on the Hub.
    repo-files          Manage files in a repo on the Hub.
    upload              Upload a file or a folder to the Hub. Recommended for single-commit uploads.
    upload-large-folder
                        Upload a large folder to the Hub. Recommended for resumable uploads.
    env                 Print information about the environment.
    version             Print information about the hf version.

options:
  -h, --help            show this help message and exit

Next steps will be to add new commands for a more consistent and feature-complete CLI, but story for another day!

[HuggingFaceDocBuilderDev]

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