Bump to ESLint 9

[jeffwidman]

This bumps to ESLint 9:

• Bump the main eslint package to v9
• Remove the eslint-config-standard package as it doesn't yet support ESLint 9 and doesn't appear to be actively maintained... I considered some of the alternatives, but they've got some drama attached (Maintenance & Governance of standard standard/standard#1948) so it seemed simplest for now to not worry about replacing it. This is a linter, so it's easy to switch to a different config if we want to later.
• Migrate to the new Flat config format:

 $ npx  @eslint/migrate-config .eslintrc.js

Migrating .eslintrc.js

WARNING: This tool does not yet work great for .eslintrc.(js|cjs|mjs) files.
It will convert the evaluated output of our config file, not the source code.
Please review the output carefully to ensure it is correct.

Also importing your .eslintignore file

Wrote new config to ./eslint.config.mjs

You will need to install the following packages to use the new config:
- globals
- @eslint/js
- @eslint/eslintrc

You can install them using the following command:

npm install globals @eslint/js @eslint/eslintrc -D

Figured I go ahead and do this one too, since I just handled this upgrade over in:

• Bump eslint from 8.57.0 to 9.22.0 github/dependabot-action#1424

[jeffwidman]

This is their new flat config file: https://eslint.org/blog/2022/08/new-config-system-part-2/

It replaces .eslintignore and .eslintrc.js...