Add option for several layers of information intensity

[JaroCamphuijsen]

It would be nice to have a visually clean way to increase or decrease the information/complexity level.

Current idea: have a switch at the top corner (can be traffic light, or [ 1 2 3 ], or something else) which will hide or show certain parts of the teaching material depending on the selected state. In this way the material can be used for various purposes.

The switch would be persistent across the platform such that a use can select the level once and navigate through all modules with this switch in this state.

Note that this will make the development of materials harder because the complexity of each level should align with other modules.

[DaniBodor]

Related to this, there could also be a "teaching view" vs a "self-study view" option.