test(benches): add basic benchmark infrastructure

[Xenira]

Refs: #599

Description

Adds basic benchmarking infrastructure

TODO:

• CI/CD integration
• Some more basic benchmarks as baseline

Checklist

Check the boxes that apply (put an x in the brackets, like [x]). You can also check boxes after the PR is created.

• I have read the contribution guidelines.
• I have added tests that prove my code works as expected.
• I have added documentation if applicable.
• I have added a migration guide if applicable.

❤️ Thank you for your contribution!

[coveralls]

Pull Request Test Coverage Report for Build 20247651182

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 36.015%

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Totals
Change from base Build 20244150814:	0.0%
Covered Lines:	1652
Relevant Lines:	4587

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💛 - Coveralls

[Xenira]

Example upload https://bencher.php.rs/perf/ext-php-rs

CI upload only works once this is merged.

[Xenira]

@ptondereau I think this works as an initial implementation. We should extend this further especially before tackling any performance issues.