Migrate to Webpack 5, updated linting and libs

[grvv]

Webpack Migration

• Migrated from Webpack v3 to v5, leveraging previous work from the v3 to v4 upgrade.
• Updated all Webpack configurations to be compatible with Webpack 5.
• Removed deprecated plugins and loaders, utilizing Webpack 5's built-in features.

Dependency Updates

• Updated Babel libraries and adjusted .babelrc configurations.
• Updated testing libraries, including Mocha and Chai.
• Fixed linting issues by updating ESLint configurations (.eslintrc).
• Ran Prettier on the codebase (npx prettier --write .) to ensure consistent code formatting.

Future Enhancements

• Plan to experiment with Rspack for potential build performance improvements.

[grvv]

Used the code from my previous PR to transition from Webpack v3 to v4 (https://github.com/mobxjs/mobx-devtools/pull/121).

[coolsoftwaretyler]

Thanks @grvv! Just got back from a work trip so I'll take a look this weekend but I suspect we'll get things merged pretty soon here.

[coolsoftwaretyler]

Looking good! There was an issue with the Electron playground with command npm run start-playground-electron, so I've fixed that in 3f596092d6aa752eee70eae87186bff80c1eb3f2. Will check the other commands one more time here.

[coolsoftwaretyler]

Everything except e2e tests is passing, and I've checked the built browser extension works in the playground. We've had problems with e2e tests for a while, so I will not block on that. Merging.

Thanks so much, @grvv!