Set interpolation options for all animation tracks at the same time.
- Enable AllTracksModifier plugin
 - Select one AnimationPlayer on SceneTreeDock
 - Run AllTracksModifier in 
Project > Tools > All Tracks Modifier... - Set options and accept dialog
 
Selected animation must be editable (not imported).
Not support Linear Angle and Cubic Angle option for value tracks, since automatically detecting angle property is difficult, and there would actually be only a few angle tracks, I determined that manually setting them one by one would not be too much trouble.
