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.

No longer needs babel, but requries an alpha version of the typescript plugin
for eslint 8 support

In newer versions there is now a normal method for this which also supports
dynamically added components.

The static version is deprecated and removed in 2.0, so we need to port here.

This has proper support for rollup while providing the same API.

This is what open-wc recommends now and uses in their @open-wc/testing package

Versions: Lit-Element to 2.4.0 and Lit-HTML to 1.3.0