feat(rust): Allow setting custom client options

[PrettyWood]

We currently use Polars in our Rust web service and need to support custom certificates in our file connector.
While this functionality already exists in object_store via the ClientOptions struct (which allows setting root certificates through the with_root_certificate method), Polars does not yet expose this struct.
This PR aims to add this capability to Polars.

Polars CloudOptions implements PartialEq, Eq and Hash, which is not the case of ClientOptions in object_store. Furthermore the defaults in polars for ClientOptions were not the same as object_store
(see get_client_options function)

So I decided to create a new type PlClientOptions with those defaults and only add what we want to set: the 3 previous fields (pure refactoring) + certificates (feature)

Some questions:

• is the overall approach good for you?
• is it ok if we ignore those certificates for PartialEq, Eq and Hash? If yes do you prefer the current approach with custom implems or the use of derivative crate with #[derivative(PartialEq="ignore")], which is more explicit and readable but adds a new dependency.
• should I simplify #[cfg(any(feature = "aws", feature = "gcp", feature = "azure", feature = "http"))] with #[cfg(feature = "cloud")]?

We can test this PR on AWS but not for GCP and Azure but since the code is the same, this test should be enough!

Thank you so much :)

[codecov]

Codecov Report

Attention: Patch coverage is 64.15094% with 19 lines in your changes missing coverage. Please review.

Project coverage is 79.20%. Comparing base (96a2d01) to head (b2ac3e9).
Report is 23 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-io/src/cloud/options.rs	64.15%	19 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #21007      +/-   ##
==========================================
- Coverage   79.34%   79.20%   -0.14%     
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  Files        1579     1583       +4     
  Lines      224319   225144     +825     
  Branches     2573     2581       +8     
==========================================
+ Hits       177976   178321     +345     
- Misses      45755    46233     +478     
- Partials      588      590       +2     

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