No functional changes.
Before this PR the interpolation mode of a new keyframe
was read from the User Preference at the deepest level
where the keyframe is created.
In case where this shouldn't be done, the flag
`INSERTKEY_NO_USERPREF` was passed in.
In this case it would fall back to some default values.
In order to make these low level functions
more flexible, the keyframe settings are now passed in.
I've made a new struct `KeyframeSettings` that holds the
* interpolation
* key type
* handle type
and a function `get_keyframe_settings` that allows
you to quickly get this settings struct.
This is a first step that will allow to pass in the
interpolation mode from python in the future.
Part of #113278
Pull Request: https://projects.blender.org/blender/blender/pulls/115898
48d35bfe53