* Allow selecting/deselecting items at container level. Previously only
  possible to select/deselect node tree leaves.
* Allow globally disabling exporting of diagrams also. Previously only
  possible to exclude documentation.
* Allow exporting also non-diagram content with attached documentation
* Allow selecting whether to include component level documentation
* Include visualization of whether exportable tree nodes actually have
  diagrams and/or documentation

gitlab #987

(cherry picked from commit 5a66a241)