Revert "Publish Christmas banner"

This reverts commit 5ac2b40.

Author: r-brown

_config.yml

@@ -21,7 +21,7 @@ dns_prefetch:
  - //l64.cc
 
 # Styling
-stage_banner_image: "../img/netlicensing-stage-banner-christmas.gif"
+stage_banner_image: "../img/netlicensing-stage-banner-01.png"
 
 # Blog
 blog_placeholder_image: "/img/blog/blog-placeholder.jpg"