Define and load animation presets from files (json, py) for sharing

[Tremeschin]

It would be great to load and define those ugly animation classes in files across Resources, direct input, or in the project Workspace so people could define their defaults, share presets, etc.

Slightly against being able to define custom python code directly for security reasons, but might have it for the most flexible controls

Probably a v0.10 thing as quite a lot needs to change