Squashed commit of the following:

commit 21309f2c
Merge: f69672e8 7a2e492e
Author: Manuel Kocher <manuel.kocher@tugraz.at>
Date:   Thu May 12 14:16:56 2022 +0200

    Merge branch 'master' into dbp-translation-component

commit f69672e8
Author: Manuel Kocher <manuel.kocher@tugraz.at>
Date:   Thu May 12 13:48:10 2022 +0200

    Remove unnecessary en translation text

commit 6d0df984
Author: Manuel Kocher <manuel.kocher@tugraz.at>
Date:   Thu May 12 13:36:45 2022 +0200

    Remove unnecessary imports and minor refactor

commit 6496d910
Author: Manuel Kocher <manuel.kocher@tugraz.at>
Date:   Thu May 12 13:24:51 2022 +0200

    Add lang-File attribute to README

commit 7a528144
Author: Manuel Kocher <manuel.kocher@tugraz.at>
Date:   Thu May 12 13:17:40 2022 +0200

    Add dbp-translation component and include it in showcase

This was used to create HTML elements for a shadow dom, but this
is now provided by the scoped-elements mixin via this.createScopedElement().

One way to handle this is enough, so remove this again.
All users have been ported already.

In case the scoped registry polyfill is loaded we need to create
elements inside of the shadowroot.

getShadowRootDocument() returns the polyfilled shadowroot, or in case
the polyfill is not loaded just return the global document, which works
in case there are no scoped registries.

In case we get something like https://github.com/open-wc/open-wc/pull/2389
this will be usefull. Also it makes IDE completion work + eslint.

This combines URLs similar to an URL join, but assumes the
base URL is the root path instead of the host.

This is useful for combining API paths with API server entry points.

Safari 12 ignores CSS applied to slots in web components.
Work around that by wrapping them in a div.

Confirmed with browserstack

This reverts commit 6324718b.

This reverts commit 3716524b.

Just change all imports and dependencies.