This moves the following `editors/*` directories to C++:
- animation, armature, lattice, mesh, metaball, object, scene.
Much of the changes in this commit (inserting casts in particular)
was automated. Further changes like switching to functional style
casts can be done separately by existing automated scripts.
See #103343
Pull Request: https://projects.blender.org/blender/blender/pulls/109715
