Add more script scaling options

[Yoooi0]

Non-uniform normalize scale type, interpolate keyframes 0%-100% towards edges (how does this work with custom default value axes)
Uniform normalize, would only work if all keyframe values are <100 or >0
Normalize based on move length? Minimum/Maximum %
Other scaling methods?
Remove current scale type? It will clip on most scripts
Prescale keyframe collection when loading (pass to script readers as options class) or do in main loop?

Add scale preview