* `Animation.TYPE_TRANSFORM3D` track is gone.
* Added POSITION_3D, ROTATION_3D, SCALE_3D tracks.
* GLTF2, Collada, FBX importers will only import the track types found.
* Skeleton3D bone poses are now Pos/Rot/Scale, pose matrix removed.
* AnimationPlayer and AnimationTree animate these tracks separately, only when found.
* Removed BakeReset code, is useless with these changes.
This is the first in a series of commits designed to make the animation system in Godot more useful, which includes:
* Better compatibility with Autodesk products
* Better reusability of animations across models (including retargeting).
* Proper animation compression.
* etc.
*Note* GLTF2 animation saving went broken with this PR, needs to be fixed in a subsequent one.
