Show progress bar for slow downloads

[konstin]

With fast internet and mainly small or cached packages, you barely even see the download spinner, but when e.g. trying to download torch on bad internet there is no indication how long this task is going to take or whether it got stuck.

[telamonian]

Yah, progress bars is one area in which the base pip has massively improved in recent years. It would be nice to have similar output by default in uv as well.

...annnd it looks like #3252 is already making it happen! Thanks guys, you're doing cool stuff

[detrin]

Ah I am so glad this was added.