Upgrade ESLint to v10

[martnpaneq]

Part of https://github.com/ckeditor/ckeditor5-internal/issues/4327.

Upgrades ESLint from v9 to v10 and aligns the shared CKEditor 5 linter packages:

• eslint → ^10.0.0
• eslint-config-ckeditor5 → ^18.0.0
• eslint-plugin-ckeditor5-rules → ^18.0.0

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[pomek]

eslint-plugin-import – this package does not support ESLint 10 (via peerDependencies)

Question: Do we need it?

[martnpaneq]

Turns out that eslint-plugin-import is not needed. We can replace a single rule that we use from it: import/extensions by rule ckeditor5-rules/require-file-extensions-in-imports.

And dropping a dependency means less maintenance in the future.