Plot Template updates (#9002)

* Ensemble plot templates now have .erpt extension and new icon
* Default plot templates are given a checkmark overlay on the icon
* Context menu has been cleaned up a bit
* Old default template is really just the last used template. Rename it.
* Add max. recursive depth setting in preferences for plot template searches
* Only create plots based on correct template type when importing ensembles or single cases
* Support creating new plot from template explorer
* Update last used template when creating a new plot from a template

ApplicationLibCode/ProjectDataModel/RimContextCommandBuilder.cpp

@@ -1024,6 +1024,8 @@ caf::CmdFeatureMenuBuilder RimContextCommandBuilder::commandsFromSelection()
         else if ( dynamic_cast<RimPlotTemplateFolderItem*>( firstUiItem ) ||
                   dynamic_cast<RimPlotTemplateFileItem*>( firstUiItem ) )
         {
+            menuBuilder << "RicCreateNewPlotFromTemplateFeature";
+            menuBuilder << "Separator";
             menuBuilder << "RicRenamePlotTemplateFeature";
             menuBuilder << "RicDeletePlotTemplateFeature";
             menuBuilder << "RicEditPlotTemplateFeature";