Simplify Webifier landing header

Author: vahidzee

configurations/nav.yml

@@ -11,4 +11,4 @@ content:
   - text: Collaborate
     link: /pages/collaboration.html
   - text: GitHub Pages
-    link: https://github.com/webifier/webifier.github.io
+    link: https://github.com/webifier

index.yml

@@ -4,7 +4,6 @@ title: Webifier
 # page header (is an object with title, description, background)
 header:
   title: Webifier
-  background: https://picsum.photos/seed/webifier/1600/900
   description: |
     Turn project content into a complete static website.