Update CFX to Bootstrap 4.x

[daeks]

[ChSchott]

Sämtliche Html bzw. Layouts dateien müssen dann den änderungen von Bootstrap angepasst werden!

[daeks]

Jquery and other JS sources need to be updated as well.

[mvrueden]

In case you are still interested in doing this, there is a pretty straight forward guide: https://getbootstrap.com/docs/4.0/migration/