The sculpt mode transform tool applies the sculpt pivot transformation to all vertices, taking XYZ symmetry into account.
This commit also includes an operator to set the pivot point initial position.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D5717
Part of T68836
`transform conversions.c` is a file that is getting too big (almost 10,000 lines).
So it's a good idea to split it into smaller files.
differential revision: https://developer.blender.org/D5677
