[test] Use vite and vitest for e2e and regression tests

[mj12albert]

• Test apps built with Vite instead of Webpack
• Tests are run with Vitest instead of Mocha
• Removed a bunch of unused devDependencies - in particular webfontloader (and some font loading code) is no longer needed as we are loading local font files

Part of https://github.com/mui/base-ui/issues/883

• [x] I have followed (at least) the PR section of the contributing guide.