Bugfix/#234 ci finetune pipelines after removing entry points

Bug fix

Summary

With this MR, the CI process checks if the build has been successful. If this is not the case (e.g. because the build script has been skipped since the entry points has been removed and a new commit is made anyway), a new HTML page, 404.html is created and put to display.

This way the pipeline won't fail after the removal of an entry point.

This MR also contains an entry point, so after having merged this, we'll be immediately able to see if this works.

Does the result of the MR comply to our "definition of done"?

• Unit tests passed
• Code reviewed
• Acceptance criteria met
• Functional tests passed
• Non-Functional requirements met
• Product Owner accepts the User Story

Closes

Closes #234 (closed).

/cc Mathias Göbel, Frank Schneider, Michelle Weidling