Transformations: rely only on albumentations features

Use directly albumentations instead of wrapping useless custom transformations

• Use probabilistic behavior
• Use built-in serialization capabilities
• Keep only an emoji transform, handling probabilistic behavior of alb

TODO:

• test in prod
• better handling of emojis font (atm, path is hardcoded in config)
• (best effort) store in db more precise informations about applied transformations
• (best effort) calidate yaml with element of albumentations expect schema