Add `socks` support (#7503)
## Summary
This adds about 50 KB to the binary:
```
❯ du ./target/release/socks
44736 ./target/release/socks
❯ du ./target/release/uv
44632 ./target/release/uv
```
So need some input on whether it's worth supporting.
Closes https://github.com/astral-sh/uv/issues/7484.
