Implement a CSRF token to protect a little more against CSRF attack.
Enhance the UI framework to allow opening a link in a new browser
window.

- Select resources from edu-sharing
- Use edu-sharing rendering service to display the resources
- Synchronize usage between OpenOLAT and edu-sharing
- Exchange configuration (metadata) between OpenOLAt and edu-sharing

If the informations (size of file, max size allowed) is available,
validate first the size client side before making a validation on the
server.

sometimes did not work properly

for TinyMCE, add validation in movie plugin, add show/hide for the
streamer, better change the size of the placeholder image...

OO-3294	: remove some specific IE 7 and 8 hacks or specific javascript libraries, update jQuery to 3.3.1