Only load css and js if a Map is displayed

[Sebobo]

It would make sense to only load the assets when there is a map node to display.

Of course, as soon as the fusion object is used, the integrator needs to modify that condition.

I can provide a PR, but it would be a breaking change for some.

[sbruggmann]

Hi @Sebobo,
Thank you for your request.

I'll like to merge this.