Add `BKE_pose_apply_action(object, action, anim_eval_context)` function
and expose in RNA as `Pose.apply_action(action, evaluation_time)`.
This makes it possible to do the following:
- Have a rig in pose mode.
- Select a subset of the bones.
- Have some Action loaded that contains the pose you want to apply.
- Run `C.object.pose.apply_pose_from_action(D.actions['PoseName'])`
- The selected bones are now posed as determined by the Action.
Just like Blender's current pose library, having no bones selected acts
the same as having all bones selected.
Manifest Task: T86159
Reviewed By: Severin
Differential Revision: https://developer.blender.org/D10578
