Make the plugin compatible for QGIS Server

[Gustry]

Describe the solution you'd like

As it's possible to have QGIS Layouts with Dataplotly component, it would be nice to have Dataplotly compatible for QGIS Server.

So we can print layouts (with or without atlas) from QGIS Server with a GetPrint request. I'm not sure what is happening right now if you give a layout with a plotly componenent inside.

It's just an idea for now ;-)

[Gustry]

Mostly done in #266

I still would like to check one thing :

• [ ] Security if the layer is filtered, or user permissions

[ghtmtt]

@Gustry I'm closing this ticket (since you have done it :) ) and eventually open other more atomic ones