Polygon filter updates (#7216)

* Rename polylinefilter to polygonfilter
* Update icon name, too
* Some GUI adjustments
* Remove obsolete code that came back in a merge somewhere.
Disable auto-enable polygon filter after picking corner points.
* Add option to delete a point in polygon filter point editor by extending generic picker interface
* Rename enum, too.
* Improved filter naming

Co-authored-by: Magne Sjaastad <magne.sjaastad@ceetronsolutions.com>

ApplicationLibCode/Commands/WellPathCommands/RicDeletePolylineTargetFeature.h

@@ -1,6 +1,6 @@
 /////////////////////////////////////////////////////////////////////////////////
 //
-//  Copyright (C) 2018-     Equinor ASA
+//  Copyright (C) 2020 Equinor ASA
 //
 //  ResInsight is free software: you can redistribute it and/or modify
 //  it under the terms of the GNU General Public License as published by
@@ -28,7 +28,6 @@ class RicDeletePolylineTargetFeature : public caf::CmdFeature
     CAF_CMD_HEADER_INIT;
 
 protected:
-    // Overrides
     bool isCommandEnabled() override;
     void onActionTriggered( bool isChecked ) override;
     void setupActionLook( QAction* actionToSetup ) override;