Improve wikidoc PDF exporting support in Generic Modeling / Diagrams to PDF

• Diagrams to PDF ➡ Model to PDF to be more accurate
• Enable exporting wikidoc for models and configuration folders
  • Allow user to toggle only the selectedness of tree container nodes like models or diagram folders instead of always toggling a whole subtree while toggling a container node in the tree
• Enable exporting wikidoc for non-diagram composite entities like libraries and structural composites
• Enable global inclusion controls, all enabled by default:
  • Include diagrams
  • Include documentation
  • Include component level documentation

Note that this does not (yet) include the possibility to toggle exporting of either diagrams or documentation on/off per entity but only globally.