Rust API for pyinitconfig

[Person-93]

Adds a rust API to initialize the embedded interpreter with configuration.

Closes #6153

[ngoldbaum]

According to codecov almost none of the API surface is tested. Can you please make sure there's coverage for all the InitConfig methods you're proposing to add?

[codspeed-hq]

Merging this PR will not alter performance

✅ 141 untouched benchmarks
⏩ 6 skipped benchmarks¹

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_{Comparing Person-93:pyinitconfig (9a0494f) with main (d44dcca)}

Footnotes

1. 6 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[Person-93]

@codspeedbot fix this regression

[Person-93]

Maintainers (@ngoldbaum), is test coverage OK. Do we need a test case which deliberately causes initialization to fail so the error handling code is covered?

[davidhewitt]

Thanks, some various thoughts and suggestions. Sorry it took a long time to get around to this one.

[davidhewitt]

Thanks, this looks good to me!

[Person-93]

The test case for successfully returning an error if initialization fails is failing on a few platforms as well as python 3.15.

I am not sure if this is because the hack I used to make the interpreter fail doesn't fail successfully on those platforms or if there is a problem with the error reporting.