Move simple index queries to CachedClient (#504)

Replaces the usage of `http-cache-reqwest` for simple index queries with
our custom cached client, removing `http-cache-reqwest` altogether.

The new cache paths are `<cache>/simple-v0/<index>/<package_name>.json`.
I could not test with a non-pypi index since i'm not aware of any other
json indices (jax and torch are both html indices).

In a future step, we can transform the response to be a
`HashMap<Version, {source_dists: Vec<(SourceDistFilename, File)>,
wheels: Vec<(WheeFilename, File)>}` (independent of python version, this
cache is used by all environments together). This should speed up cache
deserialization a bit, since we don't need to try source dist and wheel
anymore and drop incompatible dists, and it should make building the
`VersionMap` simpler. We can speed this up even further by splitting
into a version lists and the info for each version. I'm mentioning this
because deserialization was a major bottleneck in the rust part of the
old python prototype.

Fixes #481

crates/puffin-interpreter/Cargo.toml

@@ -17,7 +17,6 @@ pep440_rs = { path = "../pep440-rs" }
 pep508_rs = { path = "../pep508-rs", features = ["serde"] }
 platform-host = { path = "../platform-host" }
 
-anyhow = { workspace = true }
 cacache = { workspace = true }
 fs-err = { workspace = true, features = ["tokio"] }
 serde_json = { workspace = true }