Ie fixes

[IE-smhi]

This PR integrates the Doxygen Awesome CSS into the baltrad-topdocs project.

Key changes:

• Implemented Doxygen Awesome CSS to enhance the documentation styling.
• Upgraded the Doxygen version to the latest stable (1.9.1).
• Added a dark mode and light mode toggle for accessibility and improved readability.
• Ensured proper navigation with a responsive navigation tree for easier browsing.
• Added search functionality for improved user experience.

Preview:

Light Mode:

Dark Mode:

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Tasks:

• Added the Awesome Doxygen CSS.
• Updated Doxygen to version 1.9.1.
• Enabled the dark mode toggle.
• Improved the navigation tree for better structure.
• Fixed and optimized the search functionality.

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Testing:

• Verified the changes across various browsers (Chrome, Firefox, IE).
• Tested on mobile and desktop resolutions.
• Confirmed the dark mode and light mode toggle functions correctly.