frontpage: drop needless style-cruft

This strips a few completely needless things from the SVG-file:
- Defining the style inside the defs-tag.
- wrapping the style-contents inside CDATA: we don't use any problematic
  characters here, so this is safe without.

Acked-by: Eric Engestrom <eric@engestrom.ch>
2 jobs for master in 19 seconds
Status Job ID Name Coverage
  Test
passed #2914157
pages

00:00:19

 
  Deploy
passed pages:deploy

00:00:00