OO-1658 implement HelpTooltip componente to use the new form context help also outside of the form context

OO-1739: backport the delete button in file element and use it in user profil for the avatar, in the resource description and in the catalog entry editor

OO-1635,OO-722: refactor the ajax by iframe to use XHR, push the current business path to the browser via HTML5 push state, implements back button support via HTML5 History API...

OO-1615: springuifie mail package, rest package, question pool module... remove unused dependencies...

OO-1349: add sort in the list of settings, fix popup velocity if leading and follow-up time is missing, reload the sites gracefully, default order by begin date of list of settings

OO-1376: pluggable help link with implementation for the old help course and the new default which link to openolat confluence

OO-1254,OO-732: fix default template in certificate settings, wording, english translation, fix breadcrumb in the efficiency statement user tool

no-jira: feedback, update QTI test after closing the editor, description not mandatory on copy, footer url in the middle text, double icons in passed / failed line of the details page of a course...