When using grease pencil for drawing Storyboards, it's very common to require a transform of the layers. This transform can be done using the offset modifier, but in some cases, the scene requires a lot of modifiers and makes the file hard to work.
This new feature adds a transforms Location, Rotation and Scale at Layer level, and allows to transform the layer without using a modifier, keeping the scene more clean.
{F9480695}
This feature was suggested by @pepeland after receiving feedback from several artists.
Also, done some code cleanup and rename some functions to get a better naming.
Maniphest Tasks: T83660
Differential Revision: https://developer.blender.org/D9761
e02d84eb3b