Implement new learning content navigation/layout
* Fix first part of cypress tests
* Add event bus type to fix typecheck
* Rework SelfEvaluation to support new layout
* Fix layout
* Hide lang switcher icon in lc footer
Closes https://iterativ.atlassian.net/browse/VBV-319
* Fix cypress tests
* Unregister event bus handler
* Hide ItNavigationProgress on self evaluations with
only a single step
* Last fixes
* Merged develop into feature/new-lc-navigation
Daniel Egger
Elia Bieri