feat: PHP bindings

[Stranger6667]

• [ ] Defaults to CSSInliner (+ also rename for consistency)
• [ ] CI (tests, release)
• [ ] Docs + Readme
• [ ] inline_many
• [ ] Cache support
• [ ] namespacing?
• [x] Benchmarks
• [x] Update ext-php-rs to 0.14 when it is ready
• [ ] Cleanup tests
• [ ] Builder for options

CssInliner::inline($html)
CssInliner::options()

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #499 will not alter performance

_{Comparing dd/php (d5c1b4b) with master (98a799d)}

Summary

✅ 6 untouched benchmarks

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.43%. Comparing base (dcd2835) to head (d5c1b4b). Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #499   +/-   ##
=======================================
  Coverage   88.43%   88.43%           
=======================================
  Files          18       18           
  Lines        1919     1919           
=======================================
  Hits         1697     1697           
  Misses        222      222           

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