First iteration of new structure

New structure and initial docs of Trunks

docs/admin_guide/index.md

+# About this section
+
+All the information regarding modeling, workflows and ansible mechanics are described in this section.
+Next to this, also troubleshoting and maintainance are included.
+
+The structure is:
+
+- WFO
+  - Modelling
+  - Workflow
+  - Maintainance
+  - Troubleshoot
+- Ansible
+  - Design
+  - Low level description
+  - Troubleshoot