can now create upstream to downstream direct connections
unrelevant list elements are grayed-out

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

strip browser language to 2 letter lowercase code

update Espece translations for PAR
update doc for PAR verification

add option "messageWhenEmpty" in SelectField

+ Corrections in English documentation

Refs #428

toggle search field by clicking a search icon in the nav bar
use flex for search field

multiple terms search: all terms must match
added empty descriptions in language files for each module

move icon files into right folder
fix language code detection for more than 2 letters codes