feat: add linehaul info to uv-client (#2493)

## Summary

Closes #1958

This adds linehaul metadata to uv's user-agent when pep 508 markers are
provided to the RegistryClientBuilder. Thanks to #2381, we were able to
leverage most information from markers and avoid inconsistency.

Linehaul is meant to be accompanying metadata pip sends in it's user
agent when talking to registries. You can see this output by running
something like `python -c 'from pip._internal.network.session import
user_agent; print(user_agent())'`.
In PyPI, this metadata processed by the
[linehaul-cloud-function](https://github.com/pypi/linehaul-cloud-function).
More info about linehaul can be found in #1958.

Below are some examples from pip:

* Linux GHA: `pip/24.0
{"ci":true,"cpu":"x86_64","distro":{"id":"jammy","libc":{"lib":"glibc","version":"2.35"},"name":"Ubuntu","version":"22.04"},"implementation":{"name":"CPython","version":"3.12.2"},"installer":{"name":"pip","version":"24.0"},"openssl_version":"OpenSSL
3.0.2 15 Mar
2022","python":"3.12.2","rustc_version":"1.76.0","system":{"name":"Linux","release":"6.5.0-1016-azure"}}`
* Windows GHA: `pip/24.0
{"ci":true,"cpu":"AMD64","implementation":{"name":"CPython","version":"3.12.2"},"installer":{"name":"pip","version":"24.0"},"openssl_version":"OpenSSL
3.0.13 30 Jan
2024","python":"3.12.2","rustc_version":"1.76.0","system":{"name":"Windows","release":"2022Server"}}`
* OSX GHA: `pip/24.0
{"ci":true,"cpu":"arm64","distro":{"name":"macOS","version":"14.2.1"},"implementation":{"name":"CPython","version":"3.12.2"},"installer":{"name":"pip","version":"24.0"},"openssl_version":"OpenSSL
3.0.13 30 Jan
2024","python":"3.12.2","rustc_version":"1.76.0","system":{"name":"Darwin","release":"23.2.0"}}`



Here's how uv results look like (sorry for the keys not having the same
order):

* Linux GHA: `uv/0.1.21
{"installer":{"name":"uv","version":"0.1.21"},"python":"3.12.2","implementation":{"name":"CPython","version":"3.12.2"},"distro":{"name":"Ubuntu","version":"22.04","id":"jammy","libc":null},"system":{"name":"Linux","release":"6.5.0-1016-azure"},"cpu":"x86_64","openssl_version":null,"setuptools_version":null,"rustc_version":null,"ci":true}`
* Windows GHA: `uv/0.1.21
{"installer":{"name":"uv","version":"0.1.21"},"python":"3.12.2","implementation":{"name":"CPython","version":"3.12.2"},"distro":null,"system":{"name":"Windows","release":"2022Server"},"cpu":"AMD64","openssl_version":null,"setuptools_version":null,"rustc_version":null,"ci":true}`
* OSX GHA: `uv/0.1.21
{"installer":{"name":"uv","version":"0.1.21"},"python":"3.12.2","implementation":{"name":"CPython","version":"3.12.2"},"distro":{"name":"macOS","version":"14.2.1","id":null,"libc":null},"system":{"name":"Darwin","release":"23.2.0"},"cpu":"arm64","openssl_version":null,"setuptools_version":null,"rustc_version":null,"ci":true}`

Distro information (such as the one pip uses `from pip._vendor import
distro` to retrieve instead of `platform` module) was not retrieved from
markers. Instead, the linux release codename/name/version uses
`sys-info` crate, adding about 50us of extra overhead on linux. The
distro osx version re-used the [mac_os version
implementation](99c992e38b/crates/platform-host/src/mac_os.rs)
from #2381 which adds about 20us of overhead on osx. I tried to use
other crates to avoid re-introducing `mac_os.rs` but most of them didn't
yield satisfactory performance (40ms-60ms~) or had the wrong values
needed (e.g. darwin version vs osx version).

I also didn't add libc retrieval or rustc retrieval as those seem to add
substantial overhead due to querying `ldd` or `rustc`. PyPy version
detection was also not added to avoid adding extra overhead to [support
PyPy for
linehaul](https://github.com/pypa/pip/blob/24.0/src/pip/_internal/network/session.py#L123).
All other behavior was kept 1-1 to match what pip's linehaul
implementation does (as of 24.0). This also aligns with what was
discussed in #1958.

## Test Plan

Added new integration test to uv-client.

---------

Co-authored-by: konstin <konstin@mailbox.org>

crates/uv-client/src/lib.rs

@@ -2,6 +2,7 @@ pub use base_client::BaseClient;
 pub use cached_client::{CacheControl, CachedClient, CachedClientError, DataWithCachePolicy};
 pub use error::{BetterReqwestError, Error, ErrorKind};
 pub use flat_index::{FlatDistributions, FlatIndex, FlatIndexClient, FlatIndexError};
+pub use linehaul::LineHaul;
 pub use registry_client::{
     Connectivity, RegistryClient, RegistryClientBuilder, SimpleMetadata, SimpleMetadatum,
     VersionFiles,
@@ -14,6 +15,8 @@ mod error;
 mod flat_index;
 mod html;
 mod httpcache;
+mod linehaul;
+mod mac_version;
 mod middleware;
 mod registry_client;
 mod remote_metadata;