[FEATURE] NuttX Documentation improvement

### Is your feature request related to a problem? Please describe.

# Documentation improvement

### Describe the solution you'd like

# I am proposing to use Markdown for documentation.

## Why Markdown :
1. Its easy to use in daily routine
2. Supported by modern js frameworks (In this case -> vitepress)
3. We can leverage many graphical UI features using pt. 2 . (Inspiration - PX4-Autopilot)

Here i am attaching source and website link :
[source](https://github.com/abisop/nuttx-docs.git)
[Experimental Website](https://abisop.github.io/) - Please visit and give your feedbacks

> [Note] :
> Content is converted from rst to markdown format using automation.
> It needs some work

### Describe alternatives you've considered

_No response_

### Verification

- [x] I have verified before submitting the report.