Integrate "uv" in some way, or offer an option to swap the pip command template

[darkvertex]

How would this feature be useful?

https://github.com/astral-sh/uv is a drop-in replacement for pip which is extremely fast.

(Drop-in in the sense that generally speaking, "uv pip ..." = "pip ...")

It would greatly speed up pipx if it would call it instead of native pip.

Describe the solution you'd like

If there was some way to override which pip is called in pipx to call uv by passing it a command template, or something of the sort, could be a really nice way to make use of uv and speed up pipx runs/installs/etc.