docs: update showcase site (#577)

* docs: update showcase site

- arrange icons and descriptions in table for better overview
- add website d-koppenhagen.de

* Revert "docs: update showcase site"

This reverts commit 77d7bbe.

* docs: add d-koppenhagen.de blog showcase

Author: d-koppenhagen

docs/showcase.md

@@ -22,10 +22,13 @@ lang: en
 
 [ConfigCat Feature Flags](https://configcat.com)
 
-![soloCoding Blog](https://github.com/s0l0c0ding/solocoding/blob/master/src/assets/favicon.png)
+![soloCoding Blog](https://raw.githubusercontent.com/s0l0c0ding/solocoding/master/src/assets/favicon.png)
 
 [soloCoding Blog](https://solocoding.dev)
 
+![Danny Koppenhagen Web developer & Consultant](https://d-koppenhagen.de/assets/images/favicon.png)
+
+[Danny Koppenhagen Web developer & Consultant](https://d-koppenhagen.de)
 
 <style> 
 img {