This duplicates the language switcher on the tugraz.at site.

Compared to the previous implementation we now show the next language
and use the translations for the next language, so that users only knowing
english can understand it.

In case of more languages we just cycle through them, which isn't ideal but
good enough for now.

So we get errors with older browsers.

So we can use it directly in lit-element templates and don't have to
add an event handler to window etc.

update() is called before the actual update so we need to change i18next there.

We now listen to our own signal so multiple language selects on the same page work
and are kept in sync.

Also use the same reference for removing the event handler, bind creates a new one.

So the default gitlab config keeps working

This switches bak to the original lookup algo. Required since we
now use lerna which moves the common deps to the root package.

lit-html no longer allows merging them in literals.

No longer needed

Having two base classes for two small methods is a bit much.

Neuber, Eugen Ramon authored 5 years ago and Reiter, Christoph committed 4 years ago

See issue VPU/Apps/Library#38

Fixed upstream: https://github.com/select2/select2/issues/5682