Update task manager log levels
Move jquery context menu files to their directory
Fix client template
Pimp error message
Enhance error messages
Fix css themes
Merge pull request #914 from romainneutron/taskmanager-log-levels

[3.8] Update task manager log levels
Merge pull request #917 from romainneutron/fix-themes

[3.8] Fix css themes
Merge pull request #915 from romainneutron/error-logs

[3.8] Error logs
Merge branch '3.8'

Conflicts:
	lib/classes/task/Scheduler.php
	lib/classes/task/abstract.php
	templates/web/client/index.html.twig