Add documentation landing page to replace directory listing

[Phanindra899]

This PR adds a structured documentation landing page for the docs directory.

Currently, the docs URL renders a raw directory listing, which makes navigation difficult. This change introduces a simple and clear entry point that organizes links to key documentation sections.

The implementation is intentionally minimal and avoids introducing additional dependencies, keeping it aligned with Apache project practices.

All links directly reference the existing documentation files, ensuring consistency with the current structure.

[Phanindra899]

Hi @henrikingo,

This PR adds a structured landing page for the docs to improve navigation and onboarding.

Happy to refine the approach or make any changes based on your feedback.

Thanks!

[henrikingo]

Can you generate this from docs/README.md?

If someone wants to add one more file to docs, like JSON.md say, they should only need to add that file into one table of contents. Other formats shold be a copy of the original one, or derived from it.

[Gerrrr]

What is the value of putting an index page into this repo? If someone wants raw markdown, it is already there. I thought the point of that issue was to fix https://otava.apache.org/docs/, but then the fix should be in https://github.com/apache/otava-website.

[Phanindra899]

Hi @henrikingo , Thanks for the feedback — that makes sense.

I’ve updated the landing page to remove the manually structured content and instead reference docs/README.md as the source of truth, avoiding duplication.

However, I wanted to confirm:
Would you prefer this page to dynamically reflect the contents of README.md, or should this be handled in the otava-website repository instead?

Happy to adjust the approach accordingly.