Update HF guide with CLI guidance

[hlapp]

Using git is meanwhile often not the best way to get large or many files up on HF. Instead the CLI has been optimized for this and should be the first go-to in many cases. The corresponding part of the guide should be updated correspondingly.

[hlapp]

@egrace479 and @thompsonmj I assigned you both because I wasn't sure who'd be best positioned to take a stab, so one of you should un-assign themselves.

Also, HF has good documentation on the CLI, so maybe this can be accomplished mostly (or entirely?) by linking there and just making it clear why and when (I would say many files and/or large files) this should be the first go-to.

[egrace479]

@hlapp, I had started this refactor in the Collab Guide. I just opened a draft PR if you'd like to take a look or suggest updates/revise.

[hlapp]

Great! I commented there.