[PR3766] Make MapPathParameter property PropertyFloatConstraint instead of PropertyFloat

[TheMarkster]

https://github.com/FreeCAD/FreeCAD/pull/3766

When a sketch is attached to certain types of support we can change the MapPathParameter property to move the sketch along that support, for example if it's attached to an edge. But currently scrolling the mouse wheel to change this property changes it from 0.0 to 1.0, which is basically the range of values it can have (although you can go below zero and above 1.0 to position the sketch off the support). This PR sets the increment per scroll wheel movement to .05, which I think is a good compromise between going quickly and having some better precision.