refactor plugin setup to preset fixes search not showing,
remove unneeded plugin from package (planning#402)

tweak show/hide behaviour (planning#404)

improve responsive handling,
disable breadcrumbs (planning#404)

add matching chevron

tweak style

remove logo,
upgrade docusaurus to latest beta,
fix broken links and components after upgrade

General house keeping

Since we currently only provide one version we don't want to manage multiple (2) versions of the docs.

Erzeugen einer gepinnten 1.0.0 version (inclusive spezifischer metadata, routing-api und submission-api spec versionen)