0028467: Improve UnifySameDomain performance

This patch turns off some not needed modes of fix in the called ShapeFix_Face algorithm.

It stores pcurves on planes in the edges to avoid repeated computation of the same pcurves many times (it is done only when SafeInputMode is false).

It avoids unnecessary replace/apply actions in the modification context.

It removes the code that makes decomposition of surface of the face on several faces.

The new command buildpcurvesonplane has been added, which builds and stores pcurves of edges on planar faces. This is useful for investigations how presence of pcurves on planes influence performance of algorithms.

Make drawing of dimension line in snowflake test independent on the order of vertices in the result.

dox/dev_guides/upgrade/upgrade.md

@@ -1437,3 +1437,19 @@ The Error/Warning reporting system of the algorithms in Boolean Component (in al
 The methods returning the status of errors and warnings of the algorithms (ErrorStatus() and WarningStatus()) have been removed.
 Instead use methods HasErrors() and HasWarnings() to check for presence of errors and warnings, respectively.
 The full list of errors and warnings, with associated data such as problematic sub-shapes, can be obtained by method GetReport().
+
+@section upgrade_occt721 Upgrade to OCCT 7.2.1
+
+@subsection upgrade_721_Changes_In_USD Changes in ShapeUpgrade_UnifySameDomain
+
+The following public methods in the class ShapeUpgrade_UnifySameDomain became protected:
+* *UnifyFaces*
+* *UnifyEdges*
+
+The following public method has been removed:
+* *UnifyFacesAndEdges*
+
+@subsection upgrade_721_Move_BuildPCurveForEdgeOnPlane Moving BuildPCurveForEdgeOnPlane from BOPTools_AlgoTools2D to BRepLib
+
+The methods BuildPCurveForEdgeOnPlane and BuildPCurveForEdgesOnPlane have been moved from the class BOPTools_AlgoTools2D
+to the more lower level class BRepLib.