Readme: use links instead of build-status-buttons

closes #961

Author: cagix

readme.md

@@ -17,18 +17,12 @@ has_license: true
   [daringfireball.net]: https://daringfireball.net/2020/04/cobol_programming_coding
 
 
-::: slides
-
----
-
+::: tip
 **Read Online**:
 
-[![GitHub Preview](https://img.shields.io/github/actions/workflow/status/Programmiermethoden-CampusMinden/Prog2-Lecture/gfm.yaml?branch=master&label=GitHub%20Preview)](https://github.com/Programmiermethoden-CampusMinden/Prog2-Lecture/blob/_gfm/readme.md)
-[![Docsify Preview](https://img.shields.io/github/actions/workflow/status/Programmiermethoden-CampusMinden/Prog2-Lecture/docsify.yaml?branch=master&label=Docsify%20Preview)](https://docsify-this.net/?basePath=https://raw.githubusercontent.com/Programmiermethoden-CampusMinden/Prog2-Lecture/refs/heads/_docsify&homepage=readme.md&sidebar=true&browser-tab-title=PR2&font-size=14px&searchbox=true&externalLinkTarget=_blank&mergeNavbar=true&zoom-images=true&dark-mode=auto#/)
-[![PDF-Version](https://img.shields.io/github/actions/workflow/status/Programmiermethoden-CampusMinden/Prog2-Lecture/pdf.yaml?branch=master&label=PDF-Version)](https://github.com/Programmiermethoden-CampusMinden/Prog2-Lecture/blob/_pdf/readme.pdf)
-
----
-
+*   [GitHub Preview](https://github.com/Programmiermethoden-CampusMinden/Prog2-Lecture/blob/_gfm/readme.md)
+*   [Docsify Preview](https://docsify-this.net/?basePath=https://raw.githubusercontent.com/Programmiermethoden-CampusMinden/Prog2-Lecture/refs/heads/_docsify&homepage=readme.md&sidebar=true&browser-tab-title=PR2&font-size=14px&searchbox=true&externalLinkTarget=_blank&mergeNavbar=true&zoom-images=true&dark-mode=auto#/)
+*   [PDF-Version](https://github.com/Programmiermethoden-CampusMinden/Prog2-Lecture/blob/_pdf/readme.pdf)
 :::