0024830: Remove redundant keyword 'mutable' in CDL declarations

Redundant keyword 'mutable' removed in CDL files.
In IGESConvGeom_GeomBuilder, unused methods MakeXY() and MakeXYZ() removed.
Method StepAP214_AutoDesignGroupAssignment::Init() replicating same method of the base class is removed as it causes CDL extraction error after above (seemingly irrelevant) changes.

src/HLRTest/HLRTest_DrawableEdgeTool.cdl

@@ -33,7 +33,7 @@ is
            Rg1Line : Boolean from Standard;
            RgNLine : Boolean from Standard;
            ViewId  : Integer from Standard)
-    returns mutable DrawableEdgeTool from HLRTest;
+    returns DrawableEdgeTool from HLRTest;
     
     DrawOn(me; D : in out Display from Draw);
     

src/HLRTest/HLRTest_DrawablePolyEdgeTool.cdl

@@ -29,7 +29,7 @@ is
     Create(Alg    : PolyAlgo from HLRBRep;
            ViewId : Integer  from Standard;
            Debug  : Boolean  from Standard = Standard_False)
-    returns mutable DrawablePolyEdgeTool from HLRTest;
+    returns DrawablePolyEdgeTool from HLRTest;
     
     Show(me : mutable)
     	---C++: inline

src/HLRTest/HLRTest_OutLiner.cdl

@@ -26,7 +26,7 @@ uses
 
 is
     Create(S : Shape from TopoDS)
-    returns mutable OutLiner from HLRTest; 
+    returns OutLiner from HLRTest; 
     
     OutLiner(me) returns OutLiner from HLRTopoBRep;
 	---C++: inline
@@ -34,7 +34,7 @@ is
     DrawOn(me; dis : in out Display from Draw);
 	---Purpose: Does nothhing,
     
-    Copy(me) returns mutable Drawable3D from Draw
+    Copy(me) returns Drawable3D from Draw
 	---Purpose: For variable copy.
     is redefined;
 	

src/HLRTest/HLRTest_Projector.cdl

@@ -25,7 +25,7 @@ uses
 
 is
     Create(P : Projector from HLRAlgo)
-    returns mutable Projector from HLRTest; 
+    returns Projector from HLRTest; 
     
     Projector(me) returns Projector from HLRAlgo;
 	---C++: return const &
@@ -34,7 +34,7 @@ is
     DrawOn(me; dis : in out Display from Draw);
 	---Purpose: Does nothhing,
     
-    Copy(me) returns mutable Drawable3D from Draw
+    Copy(me) returns Drawable3D from Draw
 	---Purpose: For variable copy.
     is redefined;
 	

src/HLRTest/HLRTest_ShapeData.cdl

@@ -23,7 +23,7 @@ uses
     
 is
     Create(CVis,COVis,CIVis,CHid,COHid,CIHid : Color from Draw)
-    returns mutable ShapeData from HLRTest; 
+    returns ShapeData from HLRTest; 
     
     VisibleColor(me: mutable; CVis : Color from Draw)
     	---C++: inline