add contribute cards from internal

external/contribute/write-markdown/write-markdown.md

+---
+layout: page
+permalink: /internal/contribute/write-markdown/
+shortcut: contribute:write-markdown
+redirect_from:
+  - /cards/contribute:write-markdown
+  - /internal/cards/contribute:write-markdown
+---
+# How to write in markdown
+
+- The following symbol <img src="visual-code_img_9.png" height="20"> behind the file name means that your changes/writing is not saved.
+
+    press crt+s to save your procedure
+
+- To preview your writing click on:
+
+    <img src="visual-code_img_10.png">
+
+- **tips to write in markdown:**
+
+    <img src="visual-code_img_18.png">
+
+**insert pictures:**
+    <img src="visual-code_img_19.png" width="1000">
+
+**create a table**
+    <img src="visual-code_img_20.png">