moved config yaml to separate file

documentation/design/00-preamble.md

+---
+title: "goSDN"
+subtitle: "A networking drama"
+author: 
+  - "Martin Stiemerling"
+  - "Manuel Kieweg"
+bibliography: [./bibliography.bib]
+header-includes:
+   - \usepackage{graphicx}
+---
\ No newline at end of file