OO-1604: fix the red screen, fix the stupid warning, wording for the editors, create the tasklist object by import and copy of courses

OO-1599: fix a red screen if the task assignment step is enabled after someone started the process without it, add a confirm in the editor

OO-1589: add the download button to the members table, add setting to disable a column in the exported excel

OO-1583: if a step is disable, check that the task is not in this status and if it's the case, push the task to the next step

OO-1575: fix wrong for attribute some disabled element, for date chooser, render hour and minute for disabled date chooser element, escape blank in Confluence URL...

OO-991 i18n, xss, fix filename in download, add mail form for coach, improved status feedback, allow submission without documents, add missing identity to created files