Adding WiFiS3 API documentation

[BenjaminDannegard]

Added documentation for the WiFiS3 library to the library files and added a API.h file

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2 out of 3 committers have signed the CLA.

✅ BenjaminDannegard
✅ sebromero
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[pennam]

@BenjaminDannegard what is the status of this PR?

[BenjaminDannegard]

@BenjaminDannegard what is the status of this PR?

I am trying to fix the issues so that we can merge

[sebromero]

@BenjaminDannegard I suggest you remove the render-documentation.yml workflow from this PR and create a separate one only with that file. That will allow to merge the API docs and trouble shoot the workflow error.