feat(biome_service,biome_cli): resolve .editorconfig files and merge configuration

[dyc3]

Summary

This is part of a series of PRs to add .editorconfig support to biome. As with the previous PR, this is intentionally small to help make code reviews easier. The goal is to add functions that look for and load the .editorconfig files, and merge the loaded configurations.

Here's how the configurations are prioritized:

• cli args overrides biome.json
• biome.json overrides .editorconfig
• .editorconfig overrides biome defaults

Related to: #1724

Test Plan

I've added one test just to show that it works in this PR, but I have more tests in another branch that I could bring into this PR instead of making another one.

cargo test -p biome_service
cargo test -p biome_cli

[ematipico]

I left some suggestions and changes to improve the quality of the PR. We are almost there, we just need to add more test cases to cover the new errors

[codspeed-hq]

CodSpeed Performance Report

Merging #2884 will not alter performance

_{Comparing dyc3:05-13-editorconfig_search_for_and_load (c8455ae) with main (9a05b77)}

Summary

✅ 92 untouched benchmarks

[Sec-ant]

All my concerns are addressed, thank you ❤️

[ematipico]

Thank you for taking the time for addressing my pedantic concerns, that's really appreciated!