Empty pic in doc workaround

As pointed out in #354 (closed) - the documentation doesnt generate the pictures anymore, where saqc is run via the .fromConfig method. Local testing proofed, that this is not a doc pipeline problem, somehow with the current develop there are only empty pictures generated. I dont know what goes wrong there, and also find the interplay between config and plot and so on a little too complicated or this time of day/night - but since it is a little emberassing to have blank plots at this prominent place, i implemented a small work around and added a call to the saqc.plot method, after the .fromConfig call in a seperate plot directive -> this seems to solve the issue.