Improvements to DRC marker clearance paths.

Reverts most of the fix for 9778. Highlighting
multiple markers creates confusion in both the
status bar and how the associated clearance paths
are shown.

Also adds more clearance path graphics to make
the need for a fix to 9778 somewhat less acute.

Also makes clearance graphics scale with marker.

pcbnew/python/scripting/pcbnew_scripting_helpers.cpp

@@ -593,7 +593,7 @@ bool WriteDRCReport( BOARD* aBoard, const wxString& aFileName, EDA_UNITS aUnits,
 
     engine->SetViolationHandler(
             [&]( const std::shared_ptr<DRC_ITEM>& aItem, const VECTOR2D& aPos, int aLayer,
-                 const std::vector<PCB_SHAPE>& aShapes )
+                 const std::function<void( PCB_MARKER* )>& aPathGenerator )
             {
                 if( aItem->GetErrorCode() == DRCE_MISSING_FOOTPRINT
                     || aItem->GetErrorCode() == DRCE_DUPLICATE_FOOTPRINT