[BUGFIX] Trigger DragUploader and OnlineMedia js after loading IRRE

The DragUploader is now initialized by the requireJs callback option.
Each "Add online media by Url" button is initialized by first click.

Resolves: #70326
Releases: master
Change-Id: I5011aefa01488e073e0367ebbae1c0c615c700fd
Reviewed-on: http://review.typo3.org/43766


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>