EIoTCloudRestApiV1.0 API WifiNina intergration

[rickstaa]

I created a branch of the EasyIoT-cloud that works with the WiFi NiNA package instead of the EPS8266. This branch can be found here. I didn't create a pull request since I wasn't able to get the package compatible with both of them at the same time. Unless somebody else knows how to make the package compatible with both WiFi packages at the same time, I think it is better to create a new master_wifinina base to create the pull request on.

Multi-WiFi library support:
I think this could be done by putting the include statements of both of the libraries inside a namespace. However, after a quick search, I found out that this method is advised against (see for example this topic). I, therefore, looked at the techniques explained in this topic. I think however that it is better if somebody of the @iot-playground team decides whether integrating the WiFiNina support into the API is worth it or that it is better to keep it on a separate branch.