margin in mat-menu / new tooltips / replace purger by effacer / fix add role dialog message  / zoomin and zoomout with buttons / click on a piece show details + remove icon button to show detail / set font-family everywhere

fix: prerequires panel no longer close automatically + clear task now clear the prerequires too + clear role now clean the prerequired ressources in tasks

add comments sider-piece / resize repeat sider-piece textarea / add mat-button / replace symbolchoix and prerequires buttons by mat-buttons