Add support for children layout strategy #1339
Description
- I have checked that this feature has not yet been suggested by someone else.
Expected behavior
This feature will improve the layout engine. Soon, it will let us the possibility to contribute new children's layout strategy.
As a final user, I should not see any difference in my diagrams. I just may need to create them again.
Potential side effects
Old diagrams may work, but the layout may be broken. Creating the diagram again should fix layout issues.