Curve points/Edges(segments) custom properties(PythonAPI)

Currently, we can set custom properties(int,float,string) only for mesh's vertices/edges/polygons:

• vertices and polygons via vertex_layers/polygon_layers properties
• vertices, edges, polygons via Bmesh

Unfortunately the above doesn't apply to Curve's points(SplineBezierPoints or FCurveKeyframePoints). For last few years Curves haven't gotten any improvements and from talking to devs it turns out that it shouldn't even be time consuming task.