ESLint v9 support

[frantic1048]

ESLint v9 has two major changes that affect us:

1. Plugin API changes: Plugins need to be updated to support the new API.
2. Defaults to new "Flat Config" format: Our config files need to be reorganized to match the new format.

To upgrade to ESLint v9, we need to:

1. Update all the plugins to support the new API. Otherwise, consider replacing the plugin with alternatives.
2. Reorganize the config files to match the new format.
3. Upgrade upstream shared ESLint config to versions that support the new format. Otherwise, consider replacing the shared config with our own.

Note: Last updated on 2024-09-26.	Name	Type	Details	ESLint v9	Flat Config
eslint-config-prettier	Config	eslint-config-prettier	N/A	✅
airbnb[^2]	Config	eslint-config-airbnb-base[^2] eslint-config-airbnb/rules/react[^1] eslint-config-airbnb/rules/react-a11y[^2] eslint-config-airbnb/hooks[^2]	❌	❌
@typescript-eslint	Plugin		✅	✅
@rightcapital	Plugin		🟨[^3]	🟨[^3]
eslint-plugin-import-x	Plugin		✅	✅
eslint-plugin-jsx-a11y	Plugin		✅	✅
eslint-plugin-react [^1]	Plugin		✅	✅
eslint-react	Plugin	Replaces eslint-plugin-react[^1]	✅	✅
eslint-plugin-react-hooks	Plugin		✅	❌
eslint-plugin-lodash	Plugin		✅	✅
eslint-plugin-n	Plugin		✅	✅
eslint-plugin-simple-import-sort	Plugin		✅	✅
eslint-plugin-unicorn	Plugin		✅	✅
@stylistic/eslint-plugin-js	Plugin		✅	✅

Reference:

• https://github.com/eslint/eslint/issues/18093
• https://github.com/eslint/eslint/issues/18391
• https://eslint.org/docs/latest/extend/shareable-configs
• https://eslint.org/blog/2024/05/eslint-compatibility-utilities/

[^1]: eslint-plugin-react and eslint-config-airbnb/rules/react are deprecated in favor of eslint-react. See #156 [^2]: eslint-config-airbnb* are deprecated in favor of our own shared config. See #159, #160 [^3]: Compatible with FlatCompat from @eslint/eslintrc.

[frantic1048]

ESLint v8 will reach end of life on October 5, 2024

We may utilize @eslint/compat to help upgrade most rules to ESLint v9 without modifying the upstream implementation.

Reference: ESLint v8 End of Life Announcement