[FEATURE] docs: Generate documentation from the kconfig files

[acassis]

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

This issue is to keep track of the commit that was closed without adding the support:

https://github.com/apache/nuttx/pull/3608

Describe the solution you'd like

Many information about features of NuttX are only available in the Kconfig (when it has a ---help--- section). It is important to have the documentation about the Kconfig export to our official Documentation/

Describe alternatives you've considered

No response

Verification

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