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.
+All the information regarding modeling, workflows and Ansible mechanics are described in this section.
+Next to this, also troubleshooting and maintenance are included.
 
 The structure is:
 
 - WFO
   - Modelling
   - Workflow
-  - Maintainance
+  - Maintenance
   - Troubleshoot
 - Ansible
   - Design