DNN-26810: Save / Restore Module with Settings + Content

Problem: Often modules have more content in the "settings" than in "content". I have for example an HTML module with a lot of javascript in the head section of the settings and only one simple canvas element in the content. Exporting content only exports the canvas and nothing else.
Solution: DNN has internal methods for saving a complete page or even a complete website as a template, with all settings. But when exporting and importing module content, these methods are not used. Instead there is a special solution for this which only fetches the content and nothing else.

In this pull request I implemented this + added an additional checkbox in the import dialog for restoring the not only the modulecontent but also the settings.