App update

Submodule web/app 958856c..a48be4f:
  > Add the ajax call to create new trainee accounts in a folder
  > Patch the trainer show_folder_trainee sql selection
  > Change the import of the sql_insert_generate function in the trainer init module
  > Rename the exercises_trinee_list.user column (-> user_id)
  > Conversion dos2unix of the '27-exercises_trainee_list.sql' file
  > Force the check of the user type in the trainee listing
  > Patch the UI for the textareas in the add new user dialogs
  > Add the validation of the emails in the counting process
  > Change the help pop size for the add users to trainee list page
  > Add the 4-finger flaps to the mark search preview