no-jira: fix a red screen if an imported course has groups with areas reference but the area don't exists any more

OO-1068: fix 2 javascripts errors in IE (navbar in full screen hasn't any width, leading comma), fix an HTML error in contact form

OO-990: fix lazy loading exception if someone change the description of course, go to the course and see the details

OO-1068: reduce the rights of guest in calendar  and members course elements, fix some small issues in CSS of calendar for guest, fix missing translation in DEN

OO-1068: beautify the course element editor of "Communication and collaboration", "Administration and organisation" and "Other"