Internationalization (i18n) for Vitepress Documentation

[cgjgh]

Description

🌍Internationalization (i18n) for Dashboard 2.0 Vitepress Documentation

This PR introduces support for internationalization (i18n) in the online documentation for Dashboard 2.0, aligning its structure with the implementation method used by Vitepress for its own documentation.

Key Features:

• Reorganized documentation to follow Vitepress's i18n structure.
• Added support for the German language.

Notes:

• Future language additions can leverage this newly structured framework for simplified additions.

Related Issue(s)

Checklist

• [X] I have read the contribution guidelines
• [ ] Suitable unit/system level tests have been added and they pass
• [X] Documentation has been updated
  • [ ] Upgrade instructions
  • [ ] Configuration details
  • [ ] Concepts
• [ ] Changes flowforge.yml?
  • [ ] Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • [ ] Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• [ ] Includes a DB migration? -> add the area:migration label