OO-2409: properly set a right margin for the help and subscription to let enough place for the open button

OO-2371: check if the participant is in group of a enrollment element before allowing it to leave the course

OO-2402. don't try to launch a resource if there is nothing to launch, hardened the authentication dispatcher to accept manipulated urls and redirect them to the current page

OO-2394: harden the startup order for the folder configuration and the mail and the certificate module.