Improving effect management
## Switch to white list instead of black list
- [ ] Switch to white list (ME: would allow to check with tests if all effects are available, #1850)
- [ ] Allow custom white lists
- [ ] Allow disabling all white lists for testing / advanced users
## Add a link to the documentation for each effect
- [x] Add link to online documentation in effects / compositions info
For instance : https://docs.kdenlive.org/fr/effects_and_compositions/video_effects/alpha_mask_keying/rotoscoping.html
issue