docs: foundation and *-components usage

[mfranzke]

Which generators are impacted?

• [X] All
• [ ] HTML
• [ ] React
• [ ] Angular
• [ ] Vue
• [ ] Web components
• [ ] Power Apps

Reproduction case

Make the difference between foundation and *-components clearer. Do I need the foundation if I install the components?

Expected Behaviour

Installation instructions and package structure are clear to the users reading the documentation.

Screenshots

No response

Browser version

None

Add any other context about the problem here.

No response

[nmerget]

Will be solved in https://github.com/db-ui/mono/pull/1897