Reorder translations and add missing prefixes

- files should be prefixed with code_ocean/
- the markdown editor is part of the application (helper)

config/locales/en/meta/navigation.yml

@@ -0,0 +1,9 @@
+---
+en:
+  navigation:
+    sections:
+      contributors: Contributors
+      errors: Errors
+      files: Files
+      integrations: Integrations
+      users: Users