Add link to biotope.sh

**Is your feature request related to a problem? Please describe.**
We would like to improve the findability of the Biotope website when people are using a search engine.
A link from this repository to the parent homepage would help with that to let search engines understand that this page is important.

**Describe the solution you'd like**
Please add a link in the readme and/or in the documentation with a similar text to this:

> Biotope Element is part of Biotope, a toolchain for lasting design systems.

> Biotope helps you to build, distribute and adopt a library of web components with a consistent design and of high quality across all your websites and apps. With Biotope you can easily collaborate with your team to develop and maintain the user interface of all your digital experiences from a single location.

> If you want to learn more about Biotope and how you can benefit from using this toolchain please visit https://biotope.sh

Start with the repository README and existing documentation to find the most appropriate location for the Biotope homepage link. Add the requested Biotope description and link, then verify that the rendered documentation clearly links to https://biotope.sh.

Written by the indexing model from the issue text.