[WIP] [FEATURE] implemented smart content data-source selection and overlay slides

implemented smart content selection and overlay slides:

__Tasks:__

- [ ] test coverage
- [ ] gather feedback for my changes
- [ ] submit changes to the documentation
- [ ] overlay slide implementation
- [ ] column navigation in overlay
- [ ] selection of data source


__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | no
| Fixed tickets | none
| Doc           | none