We don't require npm to be installed

The old version is no longer maintained and doesn't support rollup v3

It has new API which we want to use.

Newest Ubuntu switched Firefox to a snap, which breaks karma.

Try to use playwright to download and cache firefox/chromium
and use those for karma.

Compared to puppeteer where we did this some time ago this caches
the browsers globally, and only downloads them when we start the tests.

This reverts commit 6324718b.

This reverts commit 3716524b.

Just change all imports and dependencies.

We still need to force the v3 format internally because i18next-scanner
doesn't support the new format and v4 drops support for Safari<13.

By setting compatibilityJSON things should continue to work as before.