This commit adds the ability to shift the involute profile inside or
outside. Profile shift is implemented as coefficient, i.e. normalized by
the module, so that it the whole profile scales with the module without
chaning shape.
To verify the profile, the tests implement an "over pins measurement"
using formulae found in literature.
Backward compatibility with FreeCAD-v0.20 is garanteed by already
existing tests, not touched by this commit.
This addresses issue #5618.
In order to not maintain the same information in two places, the property
docs are reused as tool tips for their input fields. And for user
convenience, the same tool tip is assigned to the respective label as
well.
