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

ApplicationExeCode/Resources/ResInsight.qrc

@@ -146,6 +146,7 @@
         <file>SummaryPlots16x16.png</file>
         <file>SummaryPlotsLight16x16.png</file>
         <file>SummaryTemplate16x16.png</file>
+        <file>SummaryEnsembleTemplate16x16.png</file>
         <file>SummaryXPlotLight16x16.png</file>
         <file>SummaryXPlotsLight16x16.png</file>
         <file>Swap.png</file>
@@ -267,6 +268,7 @@
         <file>AppendPrevCurve.svg</file>
         <file>AppendNextCurve.png</file>
         <file>AppendPrevCurve.png</file>
+        <file>CheckOverlay16x16.png</file>
     </qresource>
     <qresource prefix="/Shader">
         <file>fs_CellFace.glsl</file>