TEIIDDES-1947: Creates factory method for groups with fill layout

* The overlapping group title issue exists not only for groups using grid
  layout but also those using fill layout.

* WidgetFactory
 * Factory method for creating a 'simple' group with fill layout with a
   margin height of 10 to workaround the overlapping content issue.

* Fixes the most common uses of this kind of group in the datatools
  connection UI dialogs.