docs: add first skeleton for pages

docs/unified-ticketing/usage.md

+# Usage
+
+!!! todo
+    - Write how to add dependency to pom
+    - Write what repo config in pom needed

mkdocs.yml

-site_name: Unified Ticketing Doku
+site_name: Unified Ticketing Docs
 
-repo_name: 'Unified Ticketing Java Bibliothek'
+repo_name: 'Code on Transfer Portal'
 repo_url: 'https://transfer.hft-stuttgart.de/gitlab/9Lukas5/unified-ticketing'
 edit_uri: 'blob/master/docs/'
 docs_dir: docs
 
-copyright: 'Copyright © 2020 Hochschule für Technik Stuttgart'
+copyright: 'Copyright © 2020 University for Applied Sciences Stuttgart'
 
 use_directory_urls: false
 
 nav:
+  - Index: 'index.md'
   - Home:
     - Index: 'index.md'
+    - Changelog: 'unified-ticketing/changelog-softlink.md'
+    - Usage: 'unified-ticketing/usage.md'
+    - Contributing: 'unified-ticketing/contributing.md'
+    - License: 'unified-ticketing/license-softlink.md'
+  - API:
+    - Index: 'api/index.md'
+    - Core:
+      - Filter: 'api/core/filter.md'
+      - Logging: 'api/core/logging.md'
+      - Registered Systems: 'api/core/registered-systems.md'
+      - Ticket: 'api/core/ticket.md'
+      - Ticket Assignee: 'api/core/ticket-assignee.md'
+      - Ticket Builder: 'api/core/ticket-builder.md'
+      - Ticketsystem: 'api/core/ticket-system.md'
+      - Ticketsystem Builder: 'api/core/ticket-system-builder.md'
+    - Exceptions: 'api/exceptions.md'
+    - Systems:
+        - GitLab:
+          - Filter: 'api/systems/gitlab/filter.md'
+          - Ticket: 'api/systems/gitlab/ticket.md'
+          - Ticket Assignee: 'api/systems/gitlab/ticket-assignee.md'
+          - Ticket Builder: 'api/systems/gitlab/ticket-builder.md'
+          - Ticketsystem: 'api/systems/gitlab/ticket-system.md'
+          - Ticketsystem Builder: 'api/systems/gitlab/ticket-system-builder.md'
+  - Developers Guide:
+    - Index: 'dummy.md'
 
 theme:
   name: 'material'