Fixed Pos/Rot/Scl 3D Tracks insertion in SkeletonEditor

[TokageItLab]

Fixed Pos/Rot/Scl 3D Tracks insertion in SkeletonEditor to be adopt #53689. Also, implemented to pop up a dialog when inserting multiple tracks with SkeletonEditor.

I also added Animation::find_tracks(), since we now have multiple (Pos/Rot/Scl) tracks with the same path name. However, now it coexists with Animation::find_track(), so if we are not considering performance, we may as well unify Animation::find_track() into Animation::find_tracks() for maintainability.

By the way, anyone mentioned about the recording-mode in the 2D animation feature, but I think it can be added as another enhancement PR to apply it to 3D later.

[TokageItLab]

@lyuma want to get rid the popup, so I'm working on changing UI to popup's toggle into the button above and moving rest option. Probably the method itself will not change significantly, so this can be reviewed at the same time.

[TokageItLab]

Okay, it seems to be organized.

2021-10-17.7.29.33-1.mov

The reason there are two types of keying in 3DSkeleton is that, unlike 2DNodes, there are some cases where we need to avoid adding unnecessary tracks. For example, you basically don't want to insert tracks for hair or clothing bones controlled by spring bone addon, or for bones controlled by IK. Alternatively, it may be better to have the property of "keyable" on the bone itself, but for now, I am assuming the use case of generating all the bones at once, deleting the tracks that are not needed, and inserting keys only for the tracks that already exist.

Also, rest options has been moved into skeleton options, if there are more options related to rest, consider moving to another location.

[TokageItLab]

Added some shortcuts. Key insertion defaults to the "Insert" key which same as in 2D, but no default shortcuts are assigned for Init-Pose and Pose-to-Rest others due to consider to conflicts.

[lyuma]

Seems good overall to me.

Vector<int> Animation::find_tracks(const NodePath &p_path) const {

The only place I see this used is to search for a specific track by type (e.g. TYPE_ROTATION_3D). Is there ever a case where you have multiple tracks with the same path and the same type?

Maybe find_track_with_type() would be better?

[TokageItLab]

@lyuma Make sense. The previous find_track() is now unsafe and we should to replace it.

[TokageItLab]

Replaced all previous Animation::find_track(const NodePath &p_path) with Animation::find_track(const NodePath &p_path, const TrackType p_type).

[akien-mga]

Thanks!