chore: add eslint.config.js file

[tabcat]

Description

Re-exports the default aegir config from the repo root so editor plugins pick up the config and show appropriate lint warnings while developing.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works