Implement wildcard for skill search

Change the search functionality in the skills gui, to view a whitespace as a wildcard (from: https://git.h2t.iar.kit.edu/orga/software-organization/-/issues/403)

source/RobotAPI/libraries/skills_gui/skills/SkillTreeWidget.cpp

@@ -123,7 +123,7 @@ namespace armarx::skills::gui
                 }
             }
 
-            if (newProvider)
+            if (newProvider && PROVIDER_EXPANDED_DEFAULT)
                 providerItem->setExpanded(true);
         }