grey out Calculate button if basins structure is invalid
use Mermaid Nodes for walls
suffix multiple walls on same basins pair
base Mermaid Nodes on children UIDs
display Mermaid code (debug)
unselect element after deletion
highlight selected element

add basin
remove basin (buggy)
remove wall

Resolve "Calage d'une PAR: remplacer la cote de déversement par la charge"

See merge request !92

Merge branch '406-regime-uniforme-conduite-circulaire-provoquer-une-erreur-fatale-si-la-conduite-est-en-charge' into 'master'

Resolve "Régime Uniforme, conduite circulaire: provoquer une erreur fatale si la conduite est en charge"

Closes #406

See merge request !91

Resolve "Documentation de la loi Cunge80"

Closes #403

See merge request !89