Restructure vignettes

[mhallal1]

Feature description

Restructure teal vignettes such that they represent a melting point for other teal.XXX packages.
The teal vignettes should point to other packages vignettes instead of repeating information.

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct.

### Contribution Guidelines

- [X] I agree to follow this project's Contribution Guidelines.

### Security Policy

- [X] I agree to follow this project's Security Policy.

[donyunardi]

We've done couple efforts around vignettes:

• https://github.com/insightsengineering/coredev-tasks/issues/468
• https://github.com/insightsengineering/coredev-tasks/issues/467

And we'll also try to do:

• Teal development guide #807

Therefore, I'm closing this issue.
Please feel free to open a new issue for specific area of the vignette from teal.xxx package that you we think could be added to teal.