Simplify the transform code by bundling the TransData creation, Data
recalculation, and special updates into a single struct.
So similar functions and parameters can be accessed without special
type checks.
The Transform code has an extensive list of Data types.
This list keeps growing (rBd14c2d549b2f) and with it, enums and
specific conditions are added to various scattered parts of the code,
making it complicated.
So it's good to conventionalize types and functions.
Later more members can be added to the struct:
- create/free Data allocated specifically for the type
- create/free Data for snapping
- Function for calculating proportional editing factors
And others